I'm a fellow user and can provide at least some background.
Plaid is the aggregator that is used for North America. A lot of testing was done with Plaid for U.K. based customers, by a small group of testers, and while the testing has been successful Plaid have turned out not to be a viable partner outside of North America, plus their country coverage is quite limited further questioning if they would be the right global partner for software that is sold world wide.
The developer has been investigating other providers, unfortunately it seems from feedback provided that some are reluctant to partner with a company that is not U.S. based or least has a significant presence in the U.S.. Moneydance is domiciled in the U.K..
As I understand it investigations are continuing and with the current position I do not see any sort of time frame could be given for being able to provide support outside of North America.
In the interim the only realistic recommendation that can be provided is to download transaction files and import those, with OFX/QFX being the first preference, QIF the next and CSV a distant third given their general nature and inability to import into Investment Accounts.