Fitting Dog door to external wall HOW

[skybluescooby]

Just bought a Staywell dog flap to fit on a single brick wall to the garage.
Looking at the template it will leave a gap of approx 4mm from edge of hole to screw/fixing points, this means i'll have to have a precise straight cut into the brickwork which is where i'm stumped.
I understand i could fit a wooden surround but does anyone have first hand (detailed) experience as to how they did it and if so any pics ?

 

[crazycanuck]

if I understand you correctly you have a 4mm gap if so take several shingles as you would with a regular door shim up where you have the screws screw through door into brick and chauk the rest.
best wishes to bowser.