Hi Macky
You seem to have missed the irony of foxysir's contribution. A pedant would tell you that Jacobs do not make custard creams; it is cream crackers that are their speciality biscuit. Clearly then, a Jacobs custard cream would be a very valuable item - a whole packet of them so rare that it would be difficult to put a price on.
I come to the conclusion that foxysir, whilst appearing to be a critic of MdV, is in fact his greatest fan. This is in fact borne out by his first contribution. I initially made the same mistake as you in understanding his word 'crips' as a typo for 'crisps'. It is now clear to me that we have made a mistake. It was a typo, yes - but a typo for 'Cripps' - that is Harry Cripps, the Millwall cult-hero of the 1960s. Now I'm not sure what was in Harry Cripp's bags but he was a hard man, so you can be sure that it would be worth having.
Foxysir certainly had you fooled!