Winter frameset

Dolan Prefissio is cheap and well regarded by club mates, but will only take 25mm plus guards.

If you want larger than that then the Kinesis is a good buy, although you will need to buy some long drop calipers too.

Axle runners may help if there's clearance at the brakes but no mudguard eyelets http://www.sjscycles.co.uk/mobile/axiom-mudguard-axle-runners-set-of-4-p...

I think the T2 is worth a look if the 4S is too pricey:

http://road.cc/content/blog/108868-distance-new-speed

Further discussion:

http://road.cc/content/forum/154000-kinesis-frame-4s-or-t2

The rt-58 alloy is a good bike (it's the best bike in my stable) but without proper mudguard mounts I can't recommend it as a winter bike. The ribble sportive 365 might be a good bet, as mentioned above.

If you are looking for a proper winter frame set (no need for workaround mudguards) up to your budget the Kinesis 4S can be had for less than £500:

"For 2014 we have treated this unique frameset to a totally new finish, bringing it into line with our latest frames and underlining it’s All-Year capabilities by re-naming it ‘4S’, meaning ‘4 Season’.

Using our own, smooth welded ‘Kinesium’ tubeset and with clearance for full ‘guards, 28′s and long-drop brakes, this frameset makes a fantastic and well proven basis for a true 4-season bike. The 4S is a staple product for the committed racer during the winter months."

I have the cheaper T2 with mainly 105 kit on it.

Why not go carbon instead of alloy?

Planet x and ribble do carbon frames for under £300

As for running mud guards try using Crud road racer 2's as they are designed to fit road bikes with no eyelets

My winter bike/ work bike is carbon with crud road racer 2 mud guards and is used all year round

Its nice to have a light & fast bike when your spending time ridding in crappy conditions

Definitely correct for the sloping tube alu frame, not sure about the horizontal top tube alu or steel job, may be worth calling them to check.

Ribble Audax / winter frame, £110 aluminium, £175 steel plus £70 for fork - why spend more. Both equipped to take mudguards.

Winter is definitely not on the way, thank you very much!

Full guards are a must. Yes a steel frame can rust but it's your drive train that will take a bigger pasting in the wet.

Two considerations can affect your frame choices for a winter bike: (1) whether you plan to use full mudguards, and (2) the largest tyre you plan to use. I wouldn't rule out steel either, especially if you want that extra clearance.

I usually shop for winter bikes or frames on eBay (ie, secondhand).