They aren't listed ,Peter,as you prop know. Good news about matching numbers but shame about the original number do you know if it as been sold off or just lying dormant ,only if the dealers not sold it on couldn't you reclaim it , theres a guy in "old bike mag" ,sorry not sure of title now but rest assured someone will know,who would be able to give you the full sp on registrations.
Re the gap to date to sale I've certainly seen it happen but normally on cooking models like Bantams etc but it could happen to anything ,scenario usually involves more than 1 showroom and a bike thats shifted from one to another and eventually merges into the stock and gets forgotten about or even minor damage and noone wanting to admit it or maybe they weren't bike dealers and simply bought for a client who messed 'em about .I've seen that happen as well ,I used to work for Horsmans and Cundles in liverpool and some companies were to say the least were terrible with stock controll and didn't know what they'd bought .Hope you are still enjoying the bike,regards Bob.