Hi Paul,
I can think of better medals than those to the IY, the market is, at this point in time, being diven by speculators, hedge fund managers and people like Michael Ashcroft, though, to be fair to his lordship, I think he does actually get to touch and play with what he buys!
But, in the case of the former, you must understand that prices have gone up, not because of people like us, but, because of fund managers, who approach the likes of DNW, with a sum of money, "what sort of growth rate can you give me over the next five years?"
The typical reply might be 5% and so the deal is done, five years later, the said medals are either sold on again, DNW take the commission or they stay in the safe!
Yes, this is the top end of the market, but, it does have the knock on effect and what you are looking to buy increases in value and becomes harder to find.
Think about your next purchase, nothing wrong with the IY, but, I would buy something better if I were you.
As I said, market trends come and go, WO128 is nothing new, those papers have been available for ages, though, the internet is not the case.
If it is a Rhodesia clasp you want, the IY is both the easy and cheaper option, from memory, the 17th and 18th IY used to turn up a lot, but a kiwi, would be nicer!

The IY had the knack of getting into a devil of a mess, at Lindley in May 1900 for example, even my favourite, the Lovat Scouts, at Quaggafontein in September 1901, I have in my collection, the younger brother of their Adjutant who was killed in action there.
He was employed by the Colonial Office as commandant of the Constabulary in British New Guinea, after his brother had been killed, he resigned and left for South Africa, hell bent on revenge, he joined the Field Intelligence Department and spent his time on the high veldt in the Northern Transvaal.
The point is, if his brother had stayed clear of the IY and remained in his battalion he might have survived!
Anyway Paul, your money, your choice!

Regards as always Frank