We have had the Windkat for four months now and its working fine, no need to check for down drafts anymore (it looks good to).
The Windkat is working really well. I think we have been through most wind directions, with only a couple of small puffs of smoke in a seriously strong westerly. The last email I sent I had checked the flu when the wind was in the south west and there was a down draft, in the past (with other cowls) this has meant the room filling with smoke on lighting a fire. After using the Windkat I tried lighting the fire and it worked and has been working ever since.
Thank you for all your help,