Some really excellent photographic identification guides have been produced recently by our colleagues in the Netherlands. The latest is by Dr Menno Reemer of the Naturalis Biodiversity Centre in Leiden, and covers the soldierflies (Stratiomyidae) and wood-soldierflies (Xylomyidae). All but four of the British species are included.
Menno Reemer's Field key to soldierflies of the Netherlands is superbly illustrated with photos of living flies. The accompanying text is in Dutch, but with Menno's permission Jim Middleton and I have produced an English translation of the text (updated at October 2014 with minor corrections). Download both (free!) documents and you will have a really useful resource for UK soldierflies.
See also the revised identification resources page on this website for all the families covered by the recording scheme.