maybe you can somehow specify that you’re sending EUR and not GBP (which is what’s causing the expensive conversion)?
Wait, what are you sending Kraken, GBP or EUR? I just wanted to clarify that, since from what you wrote it sounds like the opposite of what TryNinja said--not that it matters much to you problem of banks being a gigantic pain in the ass and milking their customers dry at every opportunity.
It's obviously the conversion that's costing you and I'm not sure why you have to convert anyway. Doesn't Kraken accept both EUR and GBP? If not, is it possible for you to open a bank account denominated in whatever currency Kraken does accept? I can't see an obvious solution to your problem aside from switching to a bank that won't gouge you when you transfer funds to Kraken. And I'll admit that I've only used them a handful of times and that was years ago, so I haven't a clue what their business policies are nowadays.
That fee your bank is charging you sounds pretty damn high, especially if you're not depositing large sums of money. I shake my head in disbelief and wish you luck.