I've got a Warrior Assault Systems 901 OD vest, about £120 new with a load of pouches. Got mine for about £35 second hand with a few bits on it. Tons of them available pre-owned, seem very solid for the money.
I was gonna suggest the PIG UCR or WAS Nemesis, but they have inbuilt pouches on the front which is pretty sh*t in terms of customisation and if you already have the pouches. Tactical Tailor MAVs are good (and I don't just mean the Mini version) They really are small chest rigs though, not like a proper vest. The WAS 901 itself is only £70 but definitely worth the £40 for pouches.