Good (and interesting!) idea Wojtek!
The canopy I sent him is actually designed for the Tamiya kit, hence the fit problem. Falcon do a canopy for the Airfix kit aswell, but it's in closed position. - You did a great job with it mate!
PVA (white glue) applied to the seam with a toothpick should fix the gap too, although will 'sink' very slightly. Try Wojtek's trick first.