Hi Luthercalvin.
Well, this is a strange one. I had no such problem with Autoglass when I ordered my windscreen to be replaced. It sounds to me as though you’ve just got the wrong person there – why should you be doing what is their job? I would beware… any “difficulties” with them fulfilling this order, they could make your responsibility, because you’ve become a part of the order process.
I would get back to them and say that, although you’ve tried to comply with their request, it’s just not possible. This windscreen IS available, presumably from Hymer or Hymer’s glass supplier, and as Autoglass are ‘in the trade’, they are best placed to source it professionally. This is not a one-off windscreen, after all.
I would have nothing to do with supplying them with dimensions – this could backfire on you.
Any problems, ask to speak to a Manager and you can state that Autoglass have fitted several windscreens to these vehicles. There may be some confusion on their part because of the different “Exsis'” from Hymer. The Exsis they are trying to identify is Exsis SK or SG, from 2003 to 2007.
Good luck!
Barry