Massive Populus constituency polling underway - could it be Ashcroft III?

Several people have either emailed or left comments over the last couple of days to say that they've been interviewed by Populus via telephone.  It appears to be constituency polling, because the call is aborted if the interviewee turns out to be in the wrong constituency.  So far I've heard about nine seats -

Ross, Skye and Lochaber
Edinburgh North and Leith
Edinburgh South
East Dunbartonshire
Glasgow South-West
Dumfriesshire, Clydesdale and Tweeddale
Fife North-East
Berwickshire, Roxburgh and Selkirk
East Renfrewshire

From the questions that were recalled, it initially sounded like internal polling for one of the London parties, but there's no discernible pattern in the above list - other than the SNP, no party is in contention in all nine.  Another possible explanation is that it's a third round of Ashcroft constituency polls - he's already polled four of the nine seats on the list, but it could be that he's revisiting them to see if there's been any change (he's done that in a number of English constituencies).  Time will tell.

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On the previous thread, David Halliday pointed me in the direction of an article on Common Space about the current polling situation, which makes several misleading points.  In particular, it's stated that -

"In Monday's TNS Poll (TNS does face to face interviews) the headline figure for the SNP was 52 per cent but the actual raw figure before weighting was 29 per cent. The number of undecided in the TNS poll was 29 per cent - obviously these numbers are in stark contrast to what is being portrayed in the media...How the polling companies weight their polls is giving a huge boost to the SNP numbers..."

The reality is that the SNP haven't benefited at all from the weightings TNS have applied.  In respect of the headline numbers, there were 217 SNP voters before weighting, and 219 SNP voters after weighting - near-enough identical.  What is really meant by "actual raw figure before weighting" is "actual figure after weighting but before undecided respondents have been stripped out", which is an entirely different point.  Because there is such a large number of undecideds in this poll (hardly untypical for TNS), the SNP vote is of course much higher after those respondents are removed, but so is the Labour vote, the Tory vote and the Lib Dem vote.

It seems to me the average reader will be left with the highly misleading impression that all of the polling firms are using some kind of very weird weighting scheme which is uniformly flattering the SNP by a massive amount.  Nothing of the sort is happening.  YouGov's weighting tends to boost the SNP a little, but not dramatically.

The underlying message of the article is "there is no room for complacency", which I would thoroughly endorse, but I think it's possible to get that message across without making bogus points about how the SNP's position in the polls is supposedly much worse if you "drill down".   It isn't.  The SNP's position in the polls is absolutely fantastic.  If they don't win a truck-load of seats, it'll be for one (or more) of three reasons - a) a significant late swing back to Labour, b) industrial-scale tactical voting, or c) methodological flaws across the whole polling industry of the sort we saw in 1992.

On the latter point, it was mentioned on the previous thread that the SNP were significantly overestimated in the polls in the run-up to the European elections last year.  That's true, but all of the firms in question (Survation, YouGov, Panelbase and ICM) have changed their methodology since then, and introduced weighting by recalled referendum vote.  So there's no reason to assume that history is bound to repeat itself.