The goats on the BGS website do disappear often quite quickly..., and if you are after a GG pedigree billly(buckling), it may be worth your while to join the Golden Guernsey Goat Society for the princely sum of (I think) 10 pounds per year and get access to the GGGS members area on their website, so you can put a "wanted" ad on there next spring. Memberships run from Jan to Dec, so maybe best to wait until spring.
GGGS also publishes a stud list for the whole of the UK (for GGGS members only), so you may also be able to go and use a male without having to go and buy one this early on.