If anyone is following this and is interested - I had the head of EH come round this evening to do my inspection.
Plan A - Carcasses in fur to AGHE - No issues with my garage, was not fussed at all - no paperwork required other than cull record allowing traceability, all I have to do is add 2 columns to my cull register, tag number and where sold to/date.
Plan B - Processed carcass, skinned and jointed down, vacuum packed and sold to pubs/restaurants - Not in the garage. Too much other stuff in there that could contaminate, and has a carpet on the floor that would need to be changed, plus no running water/waste. This was a bit disappointing, but as we sat down in my kitchen to chat other things through, he noticed my stainless table would fit in my kitchen and that is already a 'food room' - so, much to Mrs B's dislike, carcass prep for sale will be done in my kitchen. Again, no more paperwork required and no mention of risk assesments/HACCP etc, just a record breaking down the cuts so they can be traced. Interestingly, a date is required on anything vac packed as it only has a shelf life of 10 days.
No more visits, a questionnaire to check nothing else has changed in 3 years time and I can now sell vension, rabbits, hares, pheasants etc to AGHEs and pubs/restaurants.
It may be different in other areas, but in North Kesteven that is how it is and I hope the above helps others to go through with it, had I have known that years ago I would have done it then - as those pesky animals would say - SIMPLES!