I have just been to SVA with a friends car ( first time pass) and the inspector was interested in the column and how it is fixed, i had asked him to explain as he wentr along so i could pick up tips for my car.
You need one mecanical and one elecronic means of immobalising the car, the mecanical one is the hardest because of the regs of not being able to start/stop the car etc so the ignition switch that also sets the mecanical immobalisor is by far the easiest option.
He was also keen that a motor manufacturer( the big car makers) had already had there columns approved and therefore he was happy to observe correct fitting of a known column.
To fit these, a Sierra column, to our cars usually means extending the column from the first UJ at the steering wheel end and as long as you support the column you can add further UJ's and compressable sections.
I have in total 2 UJ's changing the angle between 10 to 30 degs and 2 slidable joints with 1 crushable tube.
Also on his list of concerns was the strength of the steering support, this must be strong enough to prevent the column from being pushed forward or deflecting the steering wheel over 127mm right, left, up or down.
My current build which is not a Haynes needs the steering support hoop modified and i am using the original Ford Sierra steering support plate with the arms removed and two pieces of 3mm bar as support, that should do it.