Yes, good point. I just found the information I was looking for on their website, 'You will be able to check if you have lodged an Expression of Interest for a Bonded Medical Place by going to the Review submitted application page. If you wish to update your application to include an Expression of Interest for a Bonded Medical Place please email your request, remembering to include your UCAT number and date of birth.'Wouldn't be more convenient for you and the unis to contact them ASAP, rather than waiting until Stage 2 where you may not be able to change to bonded?
Apologies, I found what I was looking for. Thank you.