1969 5 Shillings Postage Due Jersey

I would like to show you this Postage Due stamp from Jersey 1969, one of the few unused stamps that I have and that must have come to me through some exchange, it never seems to me something really attractive in any of its aspects...But nevertheless I have seen that it is highly rated... I am very sorry for the humidity stain...

I've seen one with a BIN price of £4.29 on ebay:
https://www.ebay.co.uk/itm/313720501126
I would imagine these stamps are probably rarer postally used than unused. Quite a few collectors would have bought full sets at the time of issue, but Jersey is a small island and the amount of mail requiring a 5 shilling postage due stamp must have been minimal, though I suppose some may have been used to collect unpaid revenue on items of value sent to Jersey from overseas. And of course the adoption of decimal currency in 1971 meant that these stamps had a short service life.