The scheme, near Lichfield in Staffordshire - which received a recent £2.8 million cash injection from the Millennium Commission - aims to mark the contribution of the 16,000 British servicemen killed in action since the end of the Second World War.
O'Connor's design won a competition earlier this year, beating several Modernist entries by the likes of Chris Dyson.
But its backers are unconcerned by what seems to be a large financial hole. 'The whole thing is being underwritten by the Ministry of Defence so it will be paid for,' a spokesman for the project said.
'We still have a couple of campaigns up our sleeve that will hopefully come up with the money,' she added.