I’m putting a case to the MD for another member of staff in our tech department & as we’re well staffed at senior level, i am proposing we set on perhaps a college leaver with some Cad ability & an understanding of the construction industry.
What type of salary do you think such a position should be offering?

£18k?
See here

I’d say between 16k and 20k depending on experience and education level. For 16k you could offer a uni placement and day release. 20k should get you someone with a few years experience.

Just cad monkey or revit user btw?

Well, we’ve had revit for 3 years & never used it as there never seems time to take a step back & get fully immersed in it. Hence the need to free up some time by employing someone else.

You might be better financially, putting someone through a good revit training course. Less outlay and the person will already be fully acquainted with how your practice works.

Quite often, a new employee will be less efficient and ends up taking time from the existing resource to get them up to speed. Depends on the individual of course.