In article .com, pjh1
@tesco.net says...
Excellent idea I liked it a lot until I saw I had to cut a slot for the
bolt. I would prefer avoiding cutting any big holes through the gate
if possible which is why I wanted the big backset. I am now wondering
if I could attache the bolt to the part of the lock which goes in and
out with the key movement (whatever that is called!) and thus avoid the
slot. I'll think on this a bit longer.

You could use a rotating handle for the bolt instead of a sliding one,
but it would involve a bit more engineering.