We can transfer your subscriptions from one account to another (e.g. Power User + Yodlee), we can also migrate your client and supplier lists.
For all the existing transactions (e.g. invoices & payments) you could in theory just export the bank statement from the LTD account and import into the Sole Trader account. You can then tag all the items to create the invoice backing records.
However you need to be careful here as payments that went into the LTD company account cannot be considered as financial activity for a sole trader. The LTD is a separate legal entity.
If you have any doubts I would have a chat with your accountant who should be able to recommend the best approach.