whats the best way to exchange swiss to sterling and send back to UK?

Your bank.

I send money that arrives in my UK bank the same day in a few hours.

If you use XE or Oanda or the others that folk will inevitably recommend, you have to have an account and it takes a few days.
Any miniscule bonus in FX rates (not likely) will be more then offset by the delay and hassle

Interbank and few %

CHF 5

Yes. Any of them

And no txt spk please: it's illiterate and not all folk here are native English speakers.