The deemed export is set at 50% for everything other than hydro - which is 75%. This is included in the FITs legislation and I would expect that all suppliers will use these figures.
Thanks for this info Ted, I must have missed this detail somehow.
Anyway, it is probably about right for me at the moment though if I installed more PVs (currently 1.4kWp) then I would expect to export a higher percentage and would not be getting paid the "correct" amount. I know the emphasis is on home usage but if I can reduce my home consumption I would have thought I should be rewarded.
Maybe "smart meters" will enable a more accurate export amount to be calculated.
Simon