Hi,
I'm a 1st year at Bristol so i can actually answer a question on here for once. Basically Bristol send you a form that you have to fill in with all your vaccinations and their dates, your height and weight (they work out your BMI) and any other info that might be relevant e.g animal allergy, diabetes or dyslexia. You will need to get your form signed and stamped by your GP which they can (and usually do) charge for and you have to pay not the uni.
As far as jabs go you need to MMR, tetanus, Polio, Meningitus C, BCG etc. I was reading peoples posts about BCG, if you don't have it, it doesn't matter BUT you will have to have the Manoux test even if you passed the Heaf test (this is happening this week to the 8 or 9 people without BCG). To be honest the BCG propably is the worst injection you will have (and i hate injections) but as long as you leave it alone and don't knock it (or get punched in the arm) it will be fine - my scar is only a couple of mm across. I haven't had any hepatitus jabs or the like and only medical student need these, but if there are jabs you need they will tell you and you can get them at your GP or when you get to uni.
As far as allergies go, they can't discriminate against you for it and there are lots of people with them on the course. They are always reminding us that they are totally normal and that 1/3 of people who work with animals have or develop an allergy and they will even get you a special mask if you need one.
With learning disabilities and some other disabilities you are given extra time in exams and may be allowed to use a computer instead of writing if this helps.
I hope this post has helped to clear this all up and if you have anymore questions about Bristol, please ask.