Were I a betting man I would not put money on any of their forecasts

As is your right, of course. But that gives you two alternatives. Either you are happy to proceed into the future with your eyes tight shut and just hoping it turns out ok, or you use some other way of making a prediction. And what is that? Now, I would set some store by well thought out qualitative analyses - I don't insist on quantative. But DExEU hasn't produced these either. So we are left with 'gut feel', I think. Which I regard as inadequate.

I very much doubt, by the way, that these predictions are quite as has been reported. It is far more likely that there are confidence intervals, margins of error analysis and so on, but these are too dry for newspapers (and many MPs) to puzzle over.

In my ideal world, the model would be published, not just the results, so that it could be peer reviewed, and things that were not examined by interested parties. For example all the results assume we get a beneficial trade deal with the US. There are assumptions around this - do we get one at all, and if we do when? for example - which anyone interested enough could investigate. I'm not holding my breath on this one: it will probably be several decades before things like that are released as a matter of course.