And the answer (so far) is, NONE WHATSOEVER! +++

There's loads of the little bar stewards floating around at present, all over the car. But none coming in through the air vents any more. :D

:ROFL:
They get in EVERYWHERE, all the time. I vacuumed out SWMBO's Freelander the other day and by the time I finished, having started at the passenger side and worked around via the boot to the drivers side, the little BSs were jostling for space on the passenger seat and just waiting to blow across to the drivers side.

Your blower foam repair inspired me to check the condition of my foam Andrew.

Mine had deteriorated (felt a bit mushy/crumbly) but it was still fairly intact, so I was able to take some measurements. It was approximately 15mm high by 15mm wide.

So, after a bit of searching I found this:
http://www.ebay.co.uk/itm/NEOPRENE-R...K/351276385555
(Be sure to select the 15mm wide stuff).

On my first fitting attempt, copying the original foam, I tried separate lengths with mitred corners. That worked but I decided there was a neater, quicker solution, so I ripped it off and instead used a single piece, joined at the back. The foam goes around the corners easily and, done this way, it's a 5 minute job.

Very tidy job, Mark. +++
The stuff I bought was 19mm wide and 10mm deep, which is why I needed 2 layers in places. My old OEM stuff was in such poor condition I hadn't realised it was thicker than that.

This is the stuff I bought, it's quite firm and gives a very good seal: http://www.ebay.co.uk/itm/262290323770

You made a nice job of that mate, loving the tidy corners +++

Sorry,
Finally got around to this:
Mark's right in the 15mm x 15mm measurement.
It looks to be some sort of high density foam, bit denser than the typical interior panel anti rattle stuff.
Flat bottom, so anything of similar dimension with a self adhesive backing will do the job.
Theres nothing fancy in the material or how it's put together in the genuine factory replacement. Neoprene or some sort of generalised rubber seal might actually be a better product here I think.

Three or so years old:
https://lh3.googleusercontent.com/-w...1280/upload_-1
https://lh3.googleusercontent.com/-l...1280/upload_-1