Dump is an iconic coin that is technically the first coin struck or rather punched out of a Spanish real in Australia. Original mintage for both the holey and dump are around 40,000, 90 being too poor to be issued.
Both are definitely very collectable coins due to their historical importance. Most were recalled in 1822 to be replaced with British coinage. Supposedly 34,058 holey were redeemed but no record for the dump. Estimated survival for the holey today is around 200 - 300, dump 1000 - 2000.
Holey are coins that dealers just don't have it sitting around as they are easily 5 - 6 figure! (essentially a cheap car, home deposit or even a house in some places!). Dumps are more affordable in lower grade, but still rarely appears in the market. Most dealers would not have one as they just sell fast! There is a dealer in Sydney (Wynyard Coins) that do have one - I was lucky to see it in hand. Pretty sure it is the scarce D/2 variety. Interestingly enough, I have seen more being sold in the market recently - maybe a sign of the economy?
This is one coin that I have been hunting for years and finally purchased it a while back. I recognized it immediately from a distance, text being barely visible.

This is the common A/1 variety. This has a strong edge

I ended up getting a replica coin afterwards as it has better illustration.

This is one of those coins that rarely appear but when they do - you just have to get it especially if the price is right!
This is most likely one of those coins that I'd find it hard to upgrade unless I'm prepared to sell an arm or leg. When was the last time you saw one especially in your hands?
That said, I recall reading a thread in this forum - a member from the UK was lucky to find one in a junk box (if memory serves me right!) Might be in the world forum?