Looking for a monitor around 20" which has a display port connection. I want it to connect to my laptop as a secondary display. I am based in London so would like a UK power plug. Any suggestions?
Some Thinkpad models do have displayport, my x220 has one.
The only monitors I know of that usually have displayports are Dell's Ultraharp models but they aren't available on your budget. Your best is probably picking up a standard monitor with a DVI input and using one of these adapters. I've used one of those adapters for more than a year now and never had any issues with it.
You could go for the Dell P2210, It's probably right in that price range - 22 inches and DisplayPort. I have one and it performs admirably. Here's a list of some other DisplayPort monitors as well. If you have a little extra you could also go with the Asus VE248Q.