@JAKEISGREAT Trump is a northern word for farts in England ... so I'm guessing that @stuartgerrard85 is very close to a couple of our other wonderful members @karenben and @Lucy-licious!
I'm guessing your vet thinks it's an umbilical hernia. I think if it were anything serious that they would have done x-rays. Remind me again ... how old is Fletcher??? I'm thinking fairly young so the vet may be hoping that the hernia may just close up which I believe can happen but it's a slim chance. It would be up to you then to decide if the hernia was in any way life threatening. I have a shih-tzu poodle mix and she has an umbilical hernia. We got her in England and brought her over to Ohio with us when we moved. The vet we went to in England said it was not life threatening and so to not worry about it unless we wanted to breed her in which case it could cause problems.
By the way... where in England are you from???