Supplier refund linked to a payment without an invoice

SOLVED

I want to post a supplier refund for a cost which I posted in Sage One as type "other payment" i.e., there was no invoice from the supplier. It was a service I purchased online which I didn't fully use so the supplier has given me a part refund. The refund has come via my bank account which is linked to Sage so it is currently sitting in banking as an unallocated transaction. I've looked through help but can't find my situation. Any advice please ? Ideally I would like to link to the original posting so that it shows the refund is allocated against this cost but as the original cost was posted as "other payment", rather than an invoice (because I didn't get an invoice) - it seems hard to link ?