Linesmans fault IMO, ref has to go with him if he's confident about a decision...
I think the Ref has to tell his linesman to STFU, ref is on 18 yard line and he has final decision and has a clear view, maybe it was due to his inexperience. This game done my coupon for 400 quid. had reading to beat watford tho.
If the ref sees the incident with a good view fair enough, overule the assisstent by all means, but if he doesnt get a proper look he has to go with his assisstant who was obviously confident about his decision...