You can see the progress of the removal order in fulfilment reports > Removal Order Detail

If you click the order ID, then toggle across to "view all dispatched units". There it will show tracking information.

Alternatively, go to your manage orders, FBA page and for the sales channel at the left side, click "non amazon UK and it will show both MCF and Return Orders. For return orders, the sales channel will be just Non amazon, missing out the UK part.