When I was researching my 'Bronze' book, I came across references to these being in both the 'Martini' and 'Heinz' packs, but not the Royal Mint Uncirculated sets, so I would say this isn't especially unique or rare within its own population of rarity, if you see what I mean. Last time I saw one was at a cost of around £800, so £3400 looks like a total ramp - it's not even as though they are especially sought after, since decimal isn't on most collectors radar. For many collectors on limited budgets, decimal is an easy series to go for, but then they are not likely to spend this kind of money. For the wealthier collector, there are better things to spend £3400 on - like a 1934 crown, or something really nice from the 17th/18th Century. That probably leaves a limited number of collectors, who 'must have' every type of every denoimination and they might be willing to spend this much on what is a very mundane coin. I'll be surprised if it goes. I will second that Dave. I bought the 1984 & 1988 BU currency sets to get the 1/2p & £1...these were cheap and have gone to the back of the cupboard and haven't been seen since.