Mogas ... Ah, well there's the answer. Vince didn't say this earlier and being not familiar with the Microlight I had assumed Avgas.
The other problem our Vince now has is that Dundee doesn't list Mogas as an available fuel neither does Tayside aviation. Is Avgas100LL an acceptable alternative for a mogas motor? DND will supply Jet A1 or Avgas100LL. Odd that he should choose that as an alternate given that there are microlights at Perth but none at Dundee - and CFI at Barrow is getting the credit for vetting and giving OK to old Vince's flight plan - poor sod. PIC has to be responsible - regardless.