On Thu, 02 Nov 2006 20:52:29 +0000, Ed Sirett
wrote:

As per title. I need to keep them from going in through the air bricks.

Netlon Sentinel 'Handy Mesh' 6mm, eg:

http://www.gardenandleisure.com/products/wnet0005.html

http://www.google.co.uk/search?hl=en&safe=off&q=%22handy+mesh%22+6mm&btnG= Search&meta=cr%3DcountryUK%7CcountryGB

Local hardware shops or possibly a large shed may stock it.

cheers,
Pete.