Mo's are getting rare. The biggest problem is catching enough to make a hood.
Seriously though, welcome to the club Benc. From what I've seen people who drive in all weathers take two approaches with Westfields. One is to treat it as a motorbike with four wheels. That is to strip it out of carpets, interior trim and even seat upholstery and drill holes in the floor. You then weatherproof yourself with a waterproof suit and googles, or helmet. I take this approach. I replaced the windscreen with an aeroscreen too as I find that you would need wipers on the inside of a windscreen as well as the outside and a helmet visor clears itself at speed.
The other approach is to improve the standard Westfield wet weather gear. Modifications can be made to reduce leaks round the hood. A heater can be fitted that takes in fresh air, rather than recirculating cabin air to control condensation. From memory, GadgetMan has done this to make winter driving more civilised. It needs some work, but can be done.
Jenny