Thanks JandM, that's really helpful.
We went through old threads before we applied and I
hope we sent what they will consider sufficient evidence of partnership. We certainly meet the criteria and sent a lot of documents!
Luckily we photocopied the application before we sent it, so have it all to hand if we need to apply for an alternative visa. We thought we had done all our research regarding how long it will take for the visa to be approved, but somehow missed that it can take up to 6 months AFTER you have been assigned a CO.
Good advice to keep gathering evidence to cover the next few months - I will start doing that now.
Thanks again for your help