I have been checking the Dell UK site everyday since the very hour the new XPS models were added to the site. This morning, the prices all went up by £150, and the "original" prices shown (showing a reduction of £19.99) have also been increased so this reduction appears to be the same, but they were NEVER listed at those prices. e.g.
The top priced model with i7-10750H and 32GB RAM was originally listed at £2,949 showing a reduction of £19.99 (original price £2,968.99, which it also never was). It is now listed at £3,099 still showing a reduction of £19.99 from the "original" price of £3118.99.
I'm not sure if this also applies to the prices in other countries.
Unfortunately, I don't have the online presence to widely expose this. Hopefully someone in the community here or from the LTT team has the connections to do so.
I don't know what else to say that wouldn't be rude.