Just a quick update:
As above, I went to the MarkIV Centre, Darlington and met with Allan that same night (Monday). As Paul stated in his post, Allan is a straight up guy and is very knowledgeable. He uploaded the REVO trial software and set it to 6 6 9 (IIRC) as I use Tesco's finest. The software had a problem communicating with the ECU initially (2007MY S3), but he managed to resolve it - using a file (?) from the record saved on Paul's car.
I don't want to bore on, as there are lots of posts on this subject on ASN. BUT...the difference was immediately apparent and this is with the 80% fill. Throttle response in 1st and 2nd is far better; 3rd is as you would expect - quick; but for me 4th is the software's best moment as the increase in torque makes it a far more progressive and useful gear; there is a slight flat spot on the lower ranges of 5th, but I am sure that can be resolved; and 6th is now able to keep pace with the ebb and flow of typical UK M'way traffic (when not nose to tail).
Down side so far? *cough* 18 MPG
Currently 2.5 hrs into the 5 hr trial and work permitting I am going in on Saturday for the full map.
I will try not to make this sound like an advert, but Allan has assured me of what effectively is a FOC careplan for the life of the Map, i.e. he will adjust settings as required and re-map in the event of the worst.
I now see why those with the maps believe they transform the car. I just have to resist the urge to do anything more after
Thanks to Paul for the advice by PM.