Janos:
Never buy a truck that has been serviced privately by some man and a van, or even worse, by the owner. Buy a three year old truck from a dealer or reputable truck trader, which has been dealer maintained, and keep looking until you find a low mileage example, which will have a service history. A low mileage modern truck is totally reliable. Dealer will be able to supply all clutch measurements, oil pressure etc. Buy it, using the most tax efficient method you can, and then get a new maintenance contract with the dealer if you can afford it.
I’ve done the R&M route and found at the end, if I kept the vehicle on, their maintenance was less than optimum. Our servicing schedule is better than a main dealers. We may not be man and van, but we are a ,small company.
I’d say do what makes you feel right. Personally I’d go with a good second hand, it was years before I bought anything new!
Good luck, whatever you decide.