Keith / Wetbob,
Quite apart from knowing about the kit, it is also the case that most dealers will not supply spares "over the counter" for customers to fit themselves.
There are several reasons for this, not least the fact that implicit in handing over a spare part is the suggestion that it is therefore safe for it to be fitted by the purchaser. As many products contain lethal voltages, this is not to be advised.
Additionally, supplying a part over the counter also implies, even in non-hazardous cases, that the part is "fit-able" (if that's a word) by a typical customer. Not always/often the case.
There will always be exceptions, and the more technically minded are probably well represented on these boards, so there is a knowledge base far higher than in the general population. It can sometimes sound a bit insulting/pompous to a technically able person when a shop suggest the fitting of a new widget is the reserve of a skilled technician, when in fact 5 minutes and an allen key will have it sorted.
However, I have been present on more than one occasion when items are brought back into a shop - clearly broken/damaged from a badly done botch job - and the customer is not only asking for a refund on the now useless spare part, but also wants a complimetary repair in lieue of their time and trouble.....preferably that afternoon 
The problem is where to draw the line. One man's five minute tweak is often another man's two hour disaster - hence the reluctance to supply spare parts as if they are scart leads. It is a grey area - I know from conversations that some customers see this as sinply an attempt to obtain a service fee.
btw - Keith, you are truly a technical guru, and all-round BeoBrain.
Regards
David
Bang & Olufsen of King Street - Manchester,UK. SKYPE - beokingstreet