Hi Tony,
To my knowledge only the Gregg medals were stolen at the time, and it occurred right after the acquisition (or pending acquisition) was announced. To me, that suggests it was a targeted theft by someone who knew what they were after. Quite possibly they have spent the last 30 years deeply hidden in a personal collection, and may re-appear when that collector (or subsequent collectors who buy them in similar secrecy) eventually fail to dispose of "the goods" before their executor is selling off their effects.
Sometimes such things do reappear, see this excerpt from the Wikipedia article on
Filip Konowal (emphasis is mine):
The Victoria Cross medal
The medal went missing sometime in the 1970s, apparently stolen, and was sold to an antique shop along with some Hawaiian coins in the mid-1990s. The shop owner believed the medal was a fake, as it was inscribed with "For Valour" – evidently not realizing that all VCs awarded to Canadians had the English motto. (The source of confusion was the fact that a new Canadian VC was introduced into the Canadian Honours System in 1993, bearing the Latin motto Pro Valore). The medal was rediscovered when the shop owner offered it to the Jeffrey Hoare Auction House in London, Ontario in April 2004. A British collector discovered the auction and notified Lubomyr Luciuk, co-author of a booklet about Konowal, who took steps to have the medal secured. It was recovered by police, and returned to permanent display at the War Museum on 23 August 2004, 87 years after it was awarded.
The most important point to keep in mind, however, is that if Gregg's medals do re-appear, the Regiment does not have an automatic claim to them. They were insured, and I have been informed that an insurance policy was paid out for them Therefore the medals will go to the insurance company, which will most likely sell them to recover their loss. While we might hope that the insurance company will offer them to the Regiment, we can also expect that they will do so at current "fair market value."
If Gregg's medals do appear on the market, and the Regiment wants them, it had better be prepared to write a very large cheque. There's really no set price for VC groups, each sets its own price among the interested bidders. See this page for the range of VC prices over the past 12 years -
http://www.victoriacross.org.uk/aaauctio.htm
