I think they'll be less uptight about Coinbase, but it sounds like a convoluted process dicking around with Euros and intermediary accounts to get the best rate.
Lots of discussion about the best options on here - https://www.reddit.com/r/BitcoinUK/
Get a Nationwide account and do one large LBC sale rather than lots of small ones.
It looks like there's new regulation in Gibraltar which Wavecrest may not be complying with so they gave up - http://www.gibraltarfinance.gi/en/news/government-confirms-introduction-of-distributed-ledger-technology-dlt-regulatory-framework-in-january-2018