As for pricing, Mrs Robo had the RAC out when her Meriva wouldn't start at the stables and the chap diagnosed a dead battery (OE battery about 8 years old) he had one on the van and would fit it for £140 odd, I politely declined and bought a better make with a longer warranty from Battery Megastore for about £80..
Personally I have no issues with RAC charging a premium if they have the battery and can get you on road. Fortunately your wife was local and you were able to help. If she had been 4 hrs away and cold wet winter night then that extra £60 would be money well spent.