Options are fairly limited for that amount of inputs/outputs on a low budget.
The only thing I'd suggest in that price bracket would be the Behringer X32 Rack, with an additional Behringer S16 stagebox to give you 32 inputs, 16 outputs, which probably comes in at just under £1k.
This gives you enough inputs for everything you need now, plus spare capacity for any changing requirements in future, and 16 XLR outputs. The mixer has a total of 16 buses to be used for monitor mixes, subgroups, effects sends, so you could use 12 buses for 6 stereo IEM mixes, and have four spare for effects sends.
Not my first choice of system, but my recommended choice at sub £1k prices. It's a very common choice for touring bands who can't quite stretch to a monitor engineer yet and are carrying a self contained rig. I'm not sure there's anything else in that price bracket that you can get enough outputs from to run stereo IEMs - and you absolutely want to run them stereo wherever possible, it's a huge difference.