Mista G

I've already purchased the majority of the components and only require the motherboard to finish. I believe by the time PCIe 5 comes to use I'd be considering another upgrade then so it's not that important. The ASRock seems to be the most suggested from what I've googled and is priced nicely at £209 here in the UK where as the ASUS B650E is around £290 and ASRock B650E is £267. I did look at the MSI Edge for £199 however, I've seen quite the number of user feedback complaints.

Assuming you want to maintain PBO for Curve Optimizer undervolting, B650/E is the way to go (X670/E is a joke in ITX). Given that, there are realistically only 5 options. 
 
https://pcpartpicker.com/products/motherboard/#s=41&f=8&c=160,161&sort=price&page=1
 
If the $200 B650I Lightning Wifi does everything you need as far as I/O, I can't suggest spending any more money.
 
The only one I would NOT suggest is the Asrock B650E PG-ITX Wifi as its, at least has been, the only B650/X670 board produced without BIOS flashback.
 

I'm not familiar with the ASRock brand so usually shy away from these however, have owned a few XFX and Sapphire cards over the years and have all been great in my experience.

Thinking hard about it now as predicted my 6800 XT sold relatively easily. I've been informed by a retailer that come February, years end... price drops are coming to the 4080, 7900 XTX and 7900 XT. AIB's usually want to shift stock so might hold out till then and put some cash aside for when or if this happens.

Just managed to grab a 13600KF for £280! I can now pass on my 12400F.

Exactly the same in our household, complete mirror.

I'm keeping the Noctua, unless it isn't up to the task? My daughter's setup has the newer Hyper 212 Black V2, so that's sorted? Need to do some research next to see if it's worth the change.

More compact size, uses a 120mm fan instead of 135mm, different manufacturer and design, cheaper non-Japanese capacitors, lower temperature rating 40°C vs 50°C on the RMx, shorter warranty. Marketed as being "Low noise" it's actually no better than the other RM/RMx units, scoring A- in Cybenetics noise testing which is the same as the RMx 2021 and worse than the 2018 RMx which is A+ noise rating. Most likely due to using a more compact design and a smaller 120mm fan than the 135mm fans in the RMx/RM units.
 
Basically it's just a cheaper fully modular 80+ Gold power supply from Corsair. It's AUD $40 (~$25 USD) cheaper than the RMx models here in Australia.

Back in the day I used to own the Sapphire X1600XT and that had solid performance and build quality. Glad to hear it's remained that way. The MERC is priced a higher at £415. Remembered when XFX produced NVIDIA cards, 6600GT was my last card from them too!
 
Got some choices now... going to give it 2 weeks to see if the prices drop on both and might pull the trigger and I'll report back with my choice.

High detail would be my aim I know ultra settings are sometimes a waste. My system is built around gaming and for productivity didn't enter my thoughts.
 
 
Leaning toward the 6650 XT more now.
 
How's the drivers lately?

I would say WD SN770 is a bit better than Crucial P5 Plus
 
Crucial P5 Plus has slightly higher read speeds ( 6 GB/s vs 5..5.5 GB-ish for SN770) but that's only achieved when reading big chunks of data, not smaller chunks that would be normal when loading games, or doing things with computer on average. 
See the picture below from Tom's Hardware Review - when application/game reads in chunks of 512 KB or less, the SN770 (pink and red lines) has the edge, it can read at faster speeds than Crucial - the Crucial drive (in orange) starts to achieve higher than 4 GB/s reads only when reading chunks bigger than 512 KB which is basically only when you copy files or maybe when doing some video rendering, stuff like that.
 

 
 
When writing there's also some difference. Writing to TLC memory is slow, it's not really possible to achieve 4-5 GB/s write speeds writing directly in TLC memory. 
Drives have a SLC cache portion - basically a portion of the unused memory on the drive is "switched" into a much faster mode and used as a write cache. For example, 100 GB of free TLC memory can be converted into 25-40 GB of SLC write cache. 
So, as long as there is free space in that region of write cache memory, you get fast write speeds. When that area gets filled, the write speeds decrease, and in background the drive starts moving the data from that write cache to permanent TLC memory and then the speeds go fast again.
 
Crucial P5 Plus 1 TB seems to have up to around 100 GB of write cache, and writes in it at around 5.1 GB/s but once that's filled, it starts writing directly to TLC memory at around 1.2 .. 1.5 GB/s - in the picture below it's in TEAL (light blue), y axis is the speed in MB/s , on the x axis is time in seconds
 
The SN 770 can use much more free memory as a write cache, the review says up to 377 GB with the drive nearly empty.  They filled nearly 400 GB at almost 5 GB/s but then the write speeds dropped to around 600 MB/s when switching to writing directly to TLC memory. 
When the drive is idle, it starts moving that cached data to TLC memory at a rate of around 30 GB per minute, and the review says that as long as the write cache is only partially full, you get around 1.5 GB/s write speeds. 
 
So with the SN770 you could install a couple of 70-100 GB games at 4-5 GB/s and the write cache would still not be full, so you will rarely notice the write speeds dropping to 600 MB/s levels. 
 
Of course, when the drive gets full, this amount of write cache will decrease - if you have 600 GB out of 1 TB full, the write cache will probably be only around 30-50 GB
 

Sat directly in from of the screen the bottom left corner looks a lot lighter in colour bluish unless I move. The bottom right corner appears reddish.

Noticed the Plus is going for a great price too, missed out on some right deals there.

Really? Will wait till Friday before making a decision, see if prices fall even further.

£200/250
 
Was thinking the same, I've pretty much have the same setup as you without the GPU.