Oops... forgotten that I had placed this post!
Thank-you to all who have responded.
Anyway looks a tedious job to do so I think I'll live with the coolant loss & wait till it gets worse - it might not even be the matrix as there are no tell tale signs inside the car at the moment... Not really a fan of 'Radweld' or the like - read too many horror stories - but maybe I should give it a bash?
The 150.00 charge doesn't seem bad at all considering the lengths that are required to change the matrix - even more remarkable that the guy did the entire job in 3 hours... the matrix was definately leaking in my old Coupe & he replaced various dash bulbs too.