I wouldn't pay for an inspection as you have some protection buying from a dealer if anything goes wrong soon after buying it. You can't rely on their checks but if something fails that was suposed to have been checked you have recourse to getting it sorted. Best to take someone with you who knows about cars and will be able to spot anything obvious that would need attention - brakes, steering, sunspesion, engine management lights, gearbox noise, excessive smoking, poor power delivery. Goes without saying you must be allowed to take it for a proper test drive with no prior pressure to buy.

It should I think have had a service at four years old which will be a major service. If it hasn't then lower the price by a bit more than you were thinking of doing. They will tell you this has been factored into the price. Check if that's true with others of similar price.

10k miles a year for a diesel is pretty low so you might be wary of clogged diesel particulate filters. Ford independents can regenerate them for a fraction of the cost of a new one but still its money to be factored in to your budget.