Tue 2013-05-14 
What I think is a female Anthomyia plurinotata (Diptera: Anthomyiidae). This identification has been confirmed by Johanna van Erkelens here at Diptera.info. This species is apparently not on the UK checklist but it is on the Belgian one so it wouldn't be a big jump for it to get here.
Photo taken in Whiteknights Park, Reading, UK, on 2013-05-12
Mon 2013-05-13 
A rather docile male blowfly, probably a Bellardia sp (Diptera: Calliphoridae). I captured this specimen and later took the following photos (before I released it again):
These show the greenish abdomen more clearly.
First photo and specimen taken in the field below Chazey Wood, near Caversham, UK, on 2013-05-11.
Sun 2013-05-12 
A female Hybos sp, possibly Hybos culiciformis (Diptera: Hybotidae).
Photos taken in Whiteknights Park, Reading, UK, on 2012-10-12.
Sat 2013-05-11 
Blue leaf beetles, probably an Altica sp (Coleoptera: Chrysomelidae) on a willow herb (Epilobium sp).
Photo taken on the dam at the lower end of the large lake, Whiteknights Park, Reading, UK, on 2013-05-06.
Fri 2013-05-10 
A male Empis sp, probably Empis trigramma (Diptera: Empipidae).
Photo taken in Whiteknights Park, Reading, UK, on 2013-05-06.
