So, I thought and pop back and finish the story in case it's of any help to anyone. Good news - no babies! Advice take and we separated them. At 14 weeks Bertie was neutered and we managed to get Bella done at 16 weeks. We kept hem close to each other in separate accommodation throughout separation and regularly swapped them between hutches. We then started to re-introduce them a week after Bella's surgery (vet said that was OK). First attempt resulted in a scrap - so we left it a few days and tried again, second and third time we supervised closely for half an hour at a time. Then I put them in a slightly larger space with a hideaway hutch and tunnel and they were much more settled - him grooming her but getting nothing back. Next time in she suddenly starts grooming him and that's it, they're besties again
. Now back to living together and playing out in the garden at the same time, so much nicer for them.
Thanks for the advice - I have to say I'm glad that stressful episode is complete!