First of all, thank you for this amazing product. One of the features that I have been waiting, is to support transferring shares from a GIA to ISA account. Currently, as your support page mention, it is not possible.
Are you planning to implement this feature in a near future? Do you even have this feature on your roadmap? I believe many users are interested in this feature since they start using the free version GIA and after they reach a certain volume of shares, then it makes sense to move everything to a ISA account and pay 3£ per month.
Cheers 