@ColinJ I meant to mention this a few days ago and promptly forgot. You wondered out loud about storing your bike in Devon. A damp cold shed you said.
Well I store my bikes in a damp cold garage all year round. The summer bike is the one which sits for the winter months without moving. I've never had any problems. My routine is simply to give the bike a very thorough clean and polish the frame. The polish forms a protective film. After washing allow the bike to dry completely before putting it away. Pay particular attention to ensuring the cassette is dry.
Lube all the usual parts that I like to lube (opinion varies obviously) plus any parts prone to rusting. For example I spray a little WD40 on a rag and wipe this over hex bolt heads.
I hang the bike on the wall and drape an old sheet over it. The only time I get issues with rust, not just in winter, is if I fail to lube or dry the chain properly.
If you put the bike away clean and cared for I don't think you'll have a problem.