So I have two problems, a leaking carb and a flooding float bowl. I will try and source and replace the needle and seat but what about the bad seal? Could i try two gaskets to try and take up the low spots? I will post a picture soon.

As mentioned the surfaces are clean and the gasket is brand new. The corner castings of the float bowl do however seem to be a tad ditorted. The four screws (1 in each corner) hold the body and the float bowl togethor. In the centre of the float bowl there is a section which seals higher than the rest of the casting. When the screws are tight the centre section bottoms out and the corners will bend. This was like this when I purchased the mower second hand and after been sitting around for years. Surely someone who plays with small engines a fair bit may know or can relate to something like this?