How far apart are the slot holes in the brackets between one bracket and the other to be able to position the steering column mount accurately. It does not say in the book?

Depends what steering column you are using. I cut the plates, bolted the column to them and then mocked it all up. At least that way you know for sure that the holes fit the column.

[Edited on 24/9/13 by jps]

Sierra column hole centres are 100-101mm I think.

Sierra column I think 100 mm sounds about right muchas gracias