If you can obtain OFX/QFX, QIF or appropriately formatted CSV files from any source then they should be able to be imported into Moneydance Bank and credit card type accounts.
What you propose is not something that I think TiK would approve of. Using aggregator sites involves giving these third party organisations you Internet Banking username and passwords and this is considered by many to be a security violation as you are effectively giving someone else the keys to your bank accounts.
My reading of TIK's concerns is that they don't want to hold users' login details in case this deflects some liability onto TIK. I can understand this. So until UK banks embrace direct OFX or equivalent I need an efficient alternative. Is there something better than Money Dashboard?
As I understand it the UK legislation, and I am in Australia where Open Banking has not progressed to this stage yet, only allows for aggregators to gains assess to the information for this purpose.
TiK does not want to become an aggregator (understandable) but would like Open Banking to have provision for software on end user machines to be able to download the transaction information using the Open Banking inititive, so effectively Open Banking becomes an alternative to Direct Connect or even Quicken's Web Connect if the US were to go down that path.
I have no knowledge of aggregators in the UK. But like I said if you can get valid files they should import, personally I would prefer a format other than CSV they are more work because they are so generic, being basically just a table of information, there is the built in importer for CSV (text) files plus there are a couple that are installed as extensions that provide an alternative or give more capability, the user written CSV importer extension is I think the best tool.