2 layers of any decent thermal gear on top,needn't cost a fortune.Peter Storm stuff is good and always on sale in Millets.If it's really cold add a 100% cotton polo neck.
Bottom half,long cycling trousers and technical ski socks.Don't be put off that the socks look thin they are really warm and come up to your knee.
If the weather is really muckey and i'm on a long journey i use ordinary walking gaiters over the lower part of my trousers and boots.
Steve