It turned out that it was an Ibanez RG3270, one of their Prestige models although some rate these as J Customs. True enough the price it was going for was low, given that we'd seen it on sale for £1,300 not that long ago but it was now a discontinued model. It's got a flame maple and mahogany body, rosewood fingerboard, Edge Pro bridge, locking tremelo system, DiMarzio PAF Pro pickups in bridge and neck position and a DiMarzio Blue Velvet pickup in the mid position. Still, given that spec and build quality, it's still a stunningly good instrument and a good work through by David on it in the store soon proved that.
So that's the fourth guitar I've bought him out of Merchant City Music so far but I'm hoping I'll get some money off him for this one (fingers crossed).