Well ISP aside, I'm gonna try the USBtiny with Jacks suggestion. Might just see if the fuse settings change anything, but I have downloaded the files mentioned.
Those that have used ISP successfully.. have you run sketches that use all three INTs without problems like Jack did? if you have what (as I know it now - thanks Jack) Core do/did you use (link if pos.) I am not keen on the sandy thing as it seems a bit hackerish rather than proven main stream ( I am inventing new words as well now) :).
I have looked though the pins_xxx.h files and other trying to see if there is something obvious to change but to no avail.
I would like to try and keep this in the Arduino spirit as learning another language for this project would not be time constructive, but I fully intend to switch over on other projects (current firmware is some (streamlined) 46k so pretty large by most sketch standards.) but I do like the arduino IDE because of its basic and non-techy approach to C - its really good at making our hobby popular and the more peeps that use it the better as it seems to NOT carry a frightening inroad than other languages do., but it is fair to say once you get into this stuff you do get drawn in, so well done Arduino for bring a seemingly difficult subject to the masses. - oww sorry advert over. 
Thanks guys, Having not tried the suggestions yet I am no further forward as of tonight (UK time) but have some options to explore in the morning which is encouraging.
Steve