Glad its all sorted Sue, name and shame that LR garage, the timing should have been part of the initial checks. Demand a refund and compensation.
You are very lucky the tensioner didnt totally go. Mashed valves arent pretty, I think you got away with it

It was Riders Land Rover in Truro, Northern.

I had paid them £350 for the 4.5hrs investigative work they did but am waiting to hear back from Trading Standards as to whether I can claim it back AND refuse to pay the other Garage's Bill.