Currently there is no way of inserting a bank rec in a gap between old bank recs as the start dates of reconciliations are set to the end of the previous one only. This is an issue because it creates an ongoing problem in the figures such as subsequent "incorrect starting balances" etc. Being able to customise the start date of a reconciliation would be a great tool, preventing hours of frustration!
Have had this happen and I have un-reconciled, entered new balances then re-reconcile.