For anyone reading, I couldn't find any flights I wanted, so ended up getting Virgin Holidays in the UK to sort it - simply booked a standard economy seat on the route I wanted (as part of a holiday they booked for me) and insisted that the deal is made or broken on reward flight upgradeability - so they phoned through to flying club, confirmed the reward seats available (there's more for upgrades than full reward flights), booked at economy, quick call to FC, then 72,500 miles and £160 each later, we're in UC. Much better.
Obviously I'd have rather done the whole thing myself, but at least we're going where I wanted to, with the airline I wanted, in the cabin I wanted, and I've not been bent over for it!