I would to see a full list of which UK airfields hold/sell UL91 - but this search capability is not possible [have emailed Lisa at SD about this - it can't currently be done - but have re-enquired on this forum for others to comment]. I am able to find a single airfield and see what fuel it offers, but not the full UK list offering a specific grade of fuel.
A general search function for this and a few other things within SD might be useful and until it can be implemented, I suggest it as an enhancement here.
Some ideas of other searches that i suggest could be useful for planning our flying trips would include:
1) Which [UK] airfields offer which fuel
2) Search by runway length and refine this by choosing tarmac, grass or both
3) Search by runway orientation within a band of headings
4) Search by opening and/or closing times within a user-selected band
I'd also like to know which airfields have Hotel accommodation within a user-defined raduis, but i am probably pushing my luck . . .