The car has only 83000 kms and it is leaking just a little and decided to get the mobile mechanic in to replace the seal and thought that it would be a good idea to replace all belts and water pump. He found that the seal was loose in the housing and thought that replacing the seal would correct the leak but no good, I did ask him if he had put some loctite on the new seal and he said no so after a couple of weeks the leak restarted and he came back and fitted it with Loctite but it is still leaking so I'm thinking of having a go myself, does anyone know of any information that would help me ?

Ah, the good old TS V6!
It's a common problem on this engine - the leaking seal isn't the problem, strangely enough - it is a symptom of a different problem.

The pcv (positive crank case ventilation) system relies on several hoses and spigots on the rocker covers to keep pressure in the engine low. If the rocker covers clog up, or the hoses get blocked, or the hose that leads into the air intake gets clogged, pressure from ring blow by builds up pressure and oil oozes from places like the cam seals, and oil fill cap. The pressure can be enough to pop a seal right out.

Have a clean out of the hoses and remove the rocker cover to clean out the spigots and the space between the double layer of metal, wash out hoses, and see it it improves things.

The engine seals are designed to be pushed in by hand, need to go in square and gently - using mechanical force beyond using thumb pressure to seat them down only damages them. But if you feel the seal is too loose, loctite it in by all means.

(I had to replace a crank seal and fresh but oil damaged cam belt on one of these because the previous owner had replaced the seal and damaged it by hammering it in. Plus the lip on the seal had turned.)

had exactly same problem, seal popped sideways - did as max suggests plus the pos case valve (PCV) needed cleaning