Realized my phone autocorrected mountainsmith to a misspelling. $85 on Amazon right now.
Mountainsmith Genesee 4 Person 3 Season Tent (Lotus Blue) https://www.amazon.com/dp/B00452C2KA/ref=cm_sw_r_cp_apa_i_vEQHDbWBX4N01
(Apologies, not sure what it would be on .co.uk)
Mountainsmith makes a nice 4 man tent that will last you some time. Excellent buy for the money. A little more than you are willing to spend, but I think it will be worth it. A little under 7lbs for a 4-person tent which isn't that bad, especially for $150.
There's also the Mountainsmith Genesee through Amazon. I'm not sure it's quite as good of a tent; I did actually purchase this one back in late 2014 - here's my review of it. But it looks pretty close to the one REI was carrying; the floor looks like it was a different material, and the colors are somewhat different.