Well, then I am afraid that I can be of no help whatsoever, and I am also afraid that the probability that anybody else can help you is very close to zero. When it comes to families of flies it generally is about studying bristles, wing venation and other such hard-to-see things.
See for instance this page: Neyomyia and Eudasyphora belongs to Muscidae in Muscoidea while Lucilia and Cynomya belongs to Calliphoridae in Oestroidea and Gymnochaeta belongs to Tachinidae also in Oestroidea - and those are all easy British species. They all belong to the "section" Calyptratae, which I think applies for your specimen as well, and that is about as far as one gets. To get further and separate Oestroidea and Muscoidea one has to check for hypopleural bristles (a.k.a. meral bristles, or, as on figs 3 and 4 in this pdf, setae on the meron plate), which sometimes are somewhat hard to see on a photograph.
To my eyes it looks like one of the neotropical Syrphidae to me - hover or flower flies. There are a few genera of Calliphoridae (blow-flies) that look similar to this too though. Post to a specialist Diptera forum but do try to get better photos first!