...and don't forget that just because a (Main) dealer may not have what you're after it doesn't mean he can't get it.
When I bought my GS the salesmen went through a spec listing of available bikes that he could bring in from their 'holding' contacts. There are holdings in the UK for most manufacturers and it just takes a phone call from the dealer to their respective holders, agree an exchange with the spec you want (if available) for one of their current unsold showroom bikes and an exchange day before the bike of your choice gets shipped to the dealer you agree to buy from.