Oil leak on lower Idler/tensioner pulley

[clivealive44]

Hi, I got my cam and pump belts changed recently by a client of mine who is a Volvo mechanic, and has been for decades. He did it as a favour at his home for a very low price, said he had done them before, but a long time ago. I got him to change everything - pump belt, water pump, both idler pulleys, and cam belt.
When I got it back it was very smokey, I phoned him up, but he said he was too busy for the foreseeable future. So I managed to get the guy who did a good job on it last time to have a look at it. (he used to be a head mechanic at a Volvo franchise, and has all the tools, and had done done hundreds of them). He said the timing was well out, and it also had a bent valve. He fixed the timing and replaces all the valves.
When I got it back, it was running really well, but I noticed there was an oil leak at the front of the engine, which may have been there after the first mechanic's job. Took it back to the 2nd mechanic, he stripped it down, and found the thread for the bolt on the lower idler/tensioner pulley was damaged, and the oil was coming thru it. He tightened it as much as possible, and used some sort of thread lock/paste on the threat and the bolt head to try and seal it. The leak is now much reduced, it doesn't appear to be getting on the belt, but if you put your finger on the teeth of the cambelt pulley, or water pump pulley they are slightly damp. The 2nd mechanic said that the lower idler pulley is bolted into the oil pump, and in order to re-thread it you would have to take the oil pump out, which would involve taking the sump off. Which is a very big and expensive job.

Do people think that a slight amount of oil on the cam belt will greatly reduce it's serviceable lifetime? Any suggestions of an easier way to fix the leak?

Any advice, experiences, or suggestions welcome.