They are allowed to provide access but with a few stipulations:
Firstly, the consumer must be aware that they are sharing their data via Plaid (i.e. Plaid can't hide behind the scenes).
Secondly, there are certain exceptions for needing to be regulated by the FCA - particularly if you don't show any data back to the user.
In practice, it makes sense to be regulated by the FCA regardless because asking to share bank information/transactions with Plaid can turn users off and you're limited with what you can do with that data without being regulated/authorised.
Firstly, the consumer must be aware that they are sharing their data via Plaid (i.e. Plaid can't hide behind the scenes).
Secondly, there are certain exceptions for needing to be regulated by the FCA - particularly if you don't show any data back to the user.
In practice, it makes sense to be regulated by the FCA regardless because asking to share bank information/transactions with Plaid can turn users off and you're limited with what you can do with that data without being regulated/authorised.
Source: Fintech founder in the UK/Ireland.