Winter bike buying advice

I am in the market for a winter bike to deal with the weather that Edinburgh no doubt has in store (the summer hasn’t exactly been great so I dread to think what the winter will be like). My current winter bike is a Bianchi Via Nirone but it lacks mudguard mounts and I’ve got to the end of my tether with clip-ons. I bought new Zonda wheels towards the end of last year so they only have around 2,500km on them at the moment and the 10 speed Centaur groupset, although 7 years old, should still have some life in it yet. I’ll be using it to commute to work as well as train throughout the winter and want to be able to fit 28c tyres with mudguards (not fussed about pannier mounts). My summer bike is a SuperSix Evo Hi-Mod and I like the long and low position of that so would ideally find something similar. 

I therefore have 2 options available to me:

1) Buy a frame and transfer the groupset, wheels, bars etc. onto it. Options include the Spa Cycles Audax, Tifosi CK7 or the Kinesis Racelight 4S (which has the added benefit of being able to fit a disk groupset if I wanted to upgrade next year). Any other sensible suggestions in a similar price range welcome. I appreciate that the Spa and Tifosi aren’t particularly long and low but options seem pretty limited. 

2) Buy a complete new bike. The benefit of this is that everything would (obviously) be new and there are a lot of savings in buying a frame, wheels and groupset together. I’d also be able to get a disk groupset. The downside would be having to ditch the kit that I already have, most of which wouldn’t generate much in the way of beer tokens. Sensible suggestions (ideally under £750ish) would be welcome.

Thanks in advance.