They are excellent. A service is a look around the car, filters and oil change. They are capable of far far more so rest assured they will take care of it.
I’ve just bought my second 911 from them and both were serviced prior to collection. I’m a happy customer and in my research I was told that they had a couple of very good techs there, so I’d be confident that they’ll look after you.
I know of someone who's has just bought a high mileage 991 from Cridfords and the PDK started was playing up shortly after purchase. They replaced it with no quibbling or issues. They're now on my list of indie to look at for my next car.
My only comment on Cridfords is sometimes it's a long lead time to get booked in. But I tend to see that as a positive I guess. Bought my 981 from them and needed to go back for some warranty work. All covered and hassle free. Def recommend