The UK is host for loads of these providers.
loot.io you already mentioned.
monese.com is easy to get an account with, but costs £4,95 p/m, which for me is to expensive.
revolut.com also gives you a free UK sort account, IBAN later this year.
sogexia.com a french company that resells Raphaels, so you het a real GB-IBAN (with no sort code, but with French RIB)︀
ipagoo.com gives you a UK, FR, ES and/or IT IBAN (DE, PL, PT ongoing, rest︁ of EU and then US/AU/JP etc on the horizon) £2.5 / € 3 / $4︂ per account. Clever selfie+geolocation, to defeat Auric. Once verified, open other acounts with minimal fuss.︃
I like Revolut (free) they also working on being their own MC issuer so they︄ probably will go global again in the future.
I like Monese (Visa card), but dislike︅ their price (however that makes it a sustainable venture ...).
I like Sogexia, easy signup,︆ both French and English website.
I've not tried iPagoo, nor Loot.