Dear All,
Sorry about the long delay in resolving this post but I was out with a work thing for some months.
Anyway - Hats off to Fender GBI ! GBI contacted me directly via this thread and sent (and paid for) a UPS truck to pickup my amp take it down to their workshop where they fixed it (on warranty) and then sent it back free of charge.
On the return docket they listed replacing microphonic valves (although they are > 60 days old by now), fixing the reverb and replacing faulty reverb cable. they also wrapped a heavier magnet round the new thicker reverb cable.
Well most of the hiss has gone and it sounds like it did when I first got it - but the improvement on the reverb is quite amazing as I can turn the knob right upto 10 with only miniscule hiss after about 9 - which is awesome!
I think the Tremolo is still the PCB type but I think I will take Cpt Bb advice to get it swapped out for the real thing etc.
So in the end I have to say: Chandlers

Fender GBI
Summary:
In the beginning was a DRRI
There became a hiss problem.
Fender GBI sorted it out on warranty for free.
I am restored to Fenderness.