Hello Dr. Kara,
Thank you for your help and advice. Blue is fully vaccinated and wormed so I will do what you suggest and not feed him any food for 8 - 12 hours in the hope that will help. He doesn't seem to be in any stress at the moment i.e no tense or painful abdomen although I'm sure missing his next few meals will be surely missed by Blue as his appetite is huge !!
Thank you once again