"Back in January we had a registry office and reception venue booked, (etc ...) we had no choice but to cancel it."
"In may, we found a new venue. The contract wasn't signed until July however, due to get married in October"
Don't really understand the timing of this. As you are writing this thread in November, do you mean you are actually due to get married in October 2019?
If so I find it very strange that you were required to pay all of the ceremony, the Registrar, the Photographer, the Make-up, your dress, the cake, and the invitations. That is you paid the entire costs, the full balances, not just deposits, more than a year in advance! (Can you even do that with the Registrars fees more than a year in advance)? I don't understand that.
"It's not just the ceremony money we'd be losing, we've booked and paid for the registrar, the photographer, make up, my dress!!, the cake, all the invitations"
Or was the wedding meant to be in October past? (In which case I'd say the bird has flown).