Thanks for your helpful suggestions Helen and Elaine.
The ultrasound was to check for a possible bladder or prostate problem as Bailey has had a few infections and they wanted to check if anything was amiss there, such as stones or lumps.Fortunately his bladder is clear,although his prostrate is a bit enlarged which they think is due to an infection. He is on antibiotics for 2 weeks and then they want to rescan him to check that things have gone back to normal.It was his first time being left at the vets, so it was a bit of a stressful morning for us all.

Luckily it appears that Bailey took it all in his stride apart from being rather put out about having had no breakfast that morning. Typical cocker priorities! Also, apart from his rather revealing shave which is particularly noticable when he wags alot or at high speed (as he currently has no modesty feathering to cover his wobbly, bobbly bits!

), Bailey is as bright and mischievous as usual.
Fingers crossed that everything will clear up soon...