For 1440p gsync there are things like:
Dell S2716DG
AOC Agon AG271QG
Acer Predator XB271HU
Which are generally available around £550+ or so I think[/QUOTE
PG278QR Asus any good?
If your budget was £1900-2000 you wouldn't have had enough for an Ultima with a 1080 ti and a 1440p 144hz gsync monitor anyway I guess. i.e. you'd have a 1080 ti but not enough for a monitor to make it worth having a 1080 t. Do phone them and ask ofc.
PCS do sell the ASUS 27" ROG Swift PG278QR (1440p 144hz gsync) monitor as Lockstar mentioned, and the AOC AGON AG271QG 27" both for around £600 (and the ASUS PG279Q 27" ROG Swift which is over £700).
But if you want another monitor from elsewhere or can find a better deal on monitors on another store then go for it