Regardless of what regulation your employer is banding around he has an overall responsibility for the safety of all that visit his site, which would mean repairing pot holes and the like. I would look at pushing him with section 2 of the Health and Safety at Work Act 1974 as he has not provided you with a "Safe Place of Work". Of course there are plenty of more Acts and Regulations that would apply to your case.

I would start by asking the pub to produce their risk assessment for 1st aid? It is recomended in legislation that 1 1st aider should be provided for up to 50 people unless the risk assessemnts requires more due to the type of enviroment i.e. a childs play area should be provided with some form of first aid. Also was this ever entered into their accident book or did they refuse to do that also?

Your employeer should have carried out a PUWER assessemnt prior to placing the order for the FLT and also a risk assessment for the FLT once on your site, the Risk Assessment would then show that the suggested PSI might be considered dangerouse and then your employer is duty bound to rectify the issue once it has been documented.