Ah thanks for thinking of me and big alf Lea....he is doing fine and completely recovered and back to his mad lovable self.
We are monitoring his toilet habits which have been fine since and he is having a small amount of lactulose every few days to keep things that way, hopefully that awful event was a one off, cant really explain any reason for it so will just continue to be vigilant with him.
I have just joined so I can post.. I have just had my entire male dog operated on for something which sounds almost indentical to the symptoms you describe. He was diagnosed with a PERINEAL HERNIA. It took 2.5 months and repeated visits to the vet to have manual elimination done, plus referral (expensive) to a speciaist for an ultrasound, none of the 4 vets inc the specialist realised what the problem was. A friend recommended her vet to do colonoscopy and he diagnosed this problem virtually on the basis of case history. Sadly my boy had to be castrated as hormones do have a bearing on this but a week after surgery and he is doing well. Very best wishes to you and your boy, from someone who knows exactly what you are going through.