Can anyone shed some light on this ? I have two 14 month old british bulldogs and lately there has been an unusual foul smell coming from them, I thiink its coming from there rear end. They have been bathed twice in the last week but the smell persists, it is a smell similar to bad feet. Obviously my next step is a visit to the vet  but just wondered if any advice out there

It's most likely coming from their anal glands. The vet will no doubt empty them and the smell will stop (till the next time!)

have you any ideas what the vet fee for this would be?

Probably a bit less than an ordinary consult fee if you mention checking anal glands when booking the appointment.

It shouldn't be much - unless you have an expensive vet.  The vet will just squeeze to express the anal glands - not a pleasant job.  Imagine the smell that you are experiencing multiplied by 20!!  Get the vet to show you how to do it then you can do it yourself another time.

Thanks for that, i'll get them booked in this week

What type of tail do they have if its an invert tail it may be the smell is coming from there
especially if you have bathed them and not dried the tail properly,it could also be anal gland but double check the tail
see if you can lift it and wipe all around.