Just a quick update on this verrrrry lengthy process.........
Falco chip installed and then (long standing) clutch problem re - emerged so unable to test new chip. Fitted Oberon slave and seemed to be working fine, but leaking fluid apparently from slave. Oberon really helpful and sent replacement slave. Fitted this and still leaking

- closer examination revealed it was clutch push rod seal that was knackered (had probably been partly caused by clutch fluid on it from leaking OE slave unit)!! Seal replaced and all working well.
Moral of the story: don't assume initial presenting problem is going to the only one

- I thought slave unit was only problem (even new Oberon one!) - didn't allow for the fact that old slave unit AND push rod seal both up the creek!
With new seal installed, no more problems from clutch and no leaking engine oil - also allowed me to find out that, yes, Falco chip does work better that mille one on Falco!!
So, thanks to Fatboy for providing Falco chip and to Oberon, who were endlessly patient with my cack handed attempts at diagnosing problem - they are a really good outfit.