I have a budget of around £6-8K perhaps a little more for hardware.
You have free electricity but things can change a lot in next few years and Bitcoin Mining Difficulty is always increasing.
I don't follow prices of ASIC miners but you could probably get a few of them and earn few bucks a day in Bitcoin.
Do the ROI math yourself.
What do you think i should target with this? for maximum ROI. I know no bet is a safe bet but is it better to just stick with BTC?
Probably better to stick with bitcoin.
Mining for small players is not very profitable anymore, unless you are doing it long term, and if you are ready to take loses.
Would you have any idea of a realistic daily revenue in a pool ? and what pool do you think i should go for?
There are several different bitcoin mining calculators available online, but this are just estimates, not exact numbers.
Here is one example (select BTC):
https://www.asicminervalue.com/