David, while one should never discount incompetence as the guiding force behind anything the Scottish Conservative & Unionist party proposes in this instance I fancy indifference - rather than self-interest or incompetence - is behind Aunt Annabel's apparent admission that the party won't take a view on the Alternative Vote.
At present elections in Scotland are run using four different electoral systems: FPTP (Westminster), Additional Member System (Holyrood), Single Transferable Vote (council elections), Party List (European Elections).
In other words, there's precisely nothing sacrosanct about FPTP and, indeed, the case against it has been conceded at both the Holyrood and council level. This being so, what's the point of pretending that it's the only system that can possibly work for Westminster elections?
Far better to let politicians from all parties campaign on whatever side of the AV campaign they choose. There's no reason why this need be fought along party lines. Indeed it would be preferable if were not since, apart from anything else, whipped campaigns must suggest that each party is arguing for its own narrow interest and little else. (This might be true!)
The case for FPTP should be made on its own merits, not because of party advantage. (The same is true of the case for AV). None of them are perfect and indeed there's much that's wrong, in my view, with AMS too, but listening to campaigners for any of the options you could be forgiven for thinking that one system is wonderful and all others invite ruin.
For once, then, the Scots Tories have stumbled into a sensible place: let voters decide for themselves. Above all don't make an ass of yourself by insisting upon FPTP when you were adamant that, if there had to be a Scottish Parliament, FPTP would be a terrible idea there.
UPDATE: Plus, of course - and I should have remembered this - the AV referendum is due to be held on the same day as next year's Holyrood elections. One of those votes is more important to the Scottish Tories than the other.