I spoke briefly to ZKB branch next to my place, as it was on my way, but they seem to only handle US checks for a fee of 50 CHF.
Which Swiss bank can cash a UK check for me? I gather it won't be cheap from what I read , but I am not too sure, if that is even possible.
Im not sure if you have a UK bank account still? If so, it could be easier to post the check to them, they then credit your account and it wouldn't cost. You could then transfer electronically the money to CHF using something like Wise. I did something like that with my Nationwide account. If not, I think Postfinance might cash it, but probably for a big ish fee.
There is even better option, if you are still an owner of UK account (online).
You can cash your cheque via mobile app. There should be option available for all accounts, you just need to have enough light to scan both side of the cheque and wait ca 10 days (actually money should be available the next working day, but you still need to hold the original paper for 10 days).
It is free and quick comparing to posting cheque or travelling
Then you can transfer the money via different way to your CH account.
Hope it helps a bit.
Thanks @bwkranger and @beeze, I think this would solve my problem. Cheers!