You can see this in the new pricing too. The iPhone 13 was £779, but the iPhone 14 is £849. That's an increase of £70 (9%) in pounds, but a drop of $99 (9%) in dollars. Presumably, Apple is willing to eat a bit of exchange-rate fluctuations. Likewise, the iPhone 13 Pro was £949, but the iPhone 14 Pro is £1,099 - an increase of £150 (16%), but a decrease of $46 (3%) in dollars.
Before someone says "Apple is always overcharging UK customers - $1075 for an iPhone 13 compared to $800 in the US," it's important to note that different countries have very different regulations, fees, import tariffs, and taxes. I believe VAT in the UK is 20%.
Yes, they have dropped the price. It doesn't seem like much of a drop because most of the price decrease is in the fact that the pound has lost so much value. It's £100 cheaper than the iPhone 14 (which is what you were expecting), but it's only £30 cheaper than the iPhone 13 was a day ago (presumably in large part due to the fact that the pound is worth so much less now than a year ago).
$1,449 -> $1,399 for the 256 GB model.