Carradice Kendal Panniers - Burgundy with Black Straps - 32 Litre

I recommend this product

Classic design medium size panniers with good size rear pockets. Very well made (thanks Andrea). Single main compartment with a rear pocket with plenty of capacity for tools, inner tubes etc. Also carrying straps and rear light mounts. The base of the main compartment is solid so won't wear through.
The mounting system works for most (all?) pannier racks. It needs some setting up for the rack you are using but is then very secure yet easy to remove. However, this would also make them easy to steal so if you want to leave the bags on the bike you might need to add a lock of some sort.
The traditional straps and buckles are a bit stiff to start with but will become easier with use. Perhaps slightly larger holes in the straps would help.
Probably water resistant rather than waterproof.