It may be easier to get a auto then ?
marginally. if you already have a manual body, I'd use that. auto tunnel would make life a bit easier, but certainly is not a necessity. you could cut and weld an auto tunnel in. It would make a gearbox change easier later on - my engine almost has to come out to get the box out.

So you could not fit the reverse light switch in there because off the mounts ?
that's right.

Is there a way you could have another type or reverse light switch ?
yes. initially, when I got the car engineered and registered, I still had both the mounting brackets still in the tunnel. The reverse light switch mounted on a simple bracket under the console activated by the shifter itself.