I've never done a SEPA payment before, so i wouldn't know where to begin but I guess if I phone my bank and give them the details from Kraken they'll know what I'm going on about?
It's quite easy, actually.
You need your bank name, bank address, bank SWIFT/BIC code, your SEPA-compatible account number (if it's not presented to you normally, you can most propably find a calculator on your bank's page, or as You said, you can phone them) and your name.
Those You will input on the Kraken page.
As per EUR or USD to GBP, yeah, I don't think there are any big enough BTC/GBP markets.