Gutters and Downpipes
The guttering is a crucial part of your house's structure. Its function is to gather all the runoff from your roof and channel it into the nearest downpipe and into the drain, thus preventing a build-up of rainwater from damaging your roof or walls.
Over the summer, and even more during autumn, the gutters and downpipes can get clogged up with dirt and leaves, preventing them from doing their job, and the guttering can also sag or be damaged. If this contributes in any way to your claim, it's likely to be rejected, so check and clean your guttering at least once a year, preferably in autumn.
What to Do
The easiest solution, as always, is to get a professional in to clean out both guttering and downpipes, as well as making any repairs. It won't break the bank, although as always get several quotes and make sure you're hiring an experienced person who's charging a realistic price, rather than just taking the lowest quote.
If you choose the DIY route, you'll need a secure ladder high enough to work comfortably without stretching — and, if you're not an experienced DIYer, familiarise yourself with safety guidelines for working on a ladder. The gutters can simply be brushed out and then hosed to wash any residue down the pipes. For the downpipes themselves, you can buy a rod from any DIY shop which you push down from the top till it comes out at the bottom.
While you're up there, check the guttering for faults or damage. Sagging gutters can often be repaired by replacing screws or brackets, while cracks in PVC gutters may be repairable with mastic. Sometimes, though, the damage requires replacement.
You may not have used your radiators much over the summer, and air-pockets can build up in them, posing a risk that they'll burst. It's easy to bleed your radiators by opening the valve with a hexagonal key (if you don't have one, any hardware shop will sell them) and releasing the air till water starts to seep out — so be sure you have something to catch it. Do this to each radiator at the start of autumn, and they should run efficiently over the winter.