Ok it's been nearly 3/4 of a year in and with autumn just around the corner I decided on fitting an adjustable vent on the opposite wall to where the stove is which is where my bench is as for some reason it's the only place in the garage that wouldn't get warm, so Saturday I got my SDS drill out and cut a hole in the wall and fitted the vent but didn't have time to try it so today I got the stove going and after 1/2 an hour I opened the vent and hey presto it works and the bench area is nice and warm, just need to see how it is once winter kicks in again