A long time ago, in a galaxy far far away - well, Hull, which is pretty much the same - the very first academic article I wrote was about the post bags MPs received over the poll tax...

Conservative MPs said they found the post convincing not just because of the quantity but because: the letters didn't come from the usual suspects; they were not stock letters but personal and detailed; and they made a case that the MP found difficult to argue against.

Anyway, you can see why I mention it.

Have managed to dig up the poll tax article.

There was certainly a lot of post from constituents to MPs over the poll tax. This is how the Conservative MPs I interviewed described it:

But what really mattered was the nature of that post. It came from individuals, who were not the usual suspects, and was largely uncoordinated; letters were specific, because they were based on personal experience; they kept coming with almost no countervailing post in support.

Everything I've seen reported makes what MPs claim to be getting from constituents right now sound very similar.