Best cyclocross bike under £1000 and other CX chat

Was meaning to ask, what size randonneurs are those? Heard they come up small, and was thinking of going for 32mm but wondering if I'd also have room for mudguard. My other option is to use some cx tyres (i've some michelin mud 2s & some panaracer cindercross) but not sure about using them on the road (bit slow, wear out quickly, no room for guards?).

You can get 35's from decathlon at £15 or less, I think the sizing is correct from experience, I did have wider rims though.