Trenchcoats
This is page about the best shower proof trenches and where to get them
Clockhouse trench from Littlewoods Direct
Per Una Linen coated mac 
Mens double-breasted short mac from Marks and Spencer 
I saw one of Linea's trenches in Manchester's One of the very best! - the pic somehow doesn't do it justice, on the rail it's just adorable. Linea trench.
Clean classic styling, available in sizes up to UK26, excellent price. From Marks and Spencer
Freemans
Brilliant Teflon-coated knee-length Laura Clément trench at La Redoute