I dont suppose you could think of any questions they will ask?
At technician level I guess you'll need to know the ACPO princples and be aware of the vitalness of admissability, be familair with various pieces of hardware, know a little bit about disk geometry, the various methods of imaging, what to do/not to do at a crime scene, basic familiarity with relevant legislation, etc, etc…
I work in LE and we employed a technician last year.
His responsibilities are
The reception logging and documentation of exhibits.
The retention and safe custody of those exhibits whilst in our custody.
The return or destruction of exhibits after the case has concluded.
Maintaining chain of custody matters re the above
All imaging procedures (Windows, Dos, Linux both onsite and offsite). To achieve this he has obviously accompanied us on jobs and been subject to ongoing inhouse training (including Encase Intermediate course).
All backups etc and general office administration.
On top of that as he progresses he is sitting on our shoulders as we do examinations and asking lots of questions and generally being a nuisance (only joking).
Best advice is show an interest and read up on the ACPO guidelines especially in your case relating to chain of custody and care and control of exhibits.
Also think hard for an answer to a question that must be asked relating to how you will cope with some of the more horrific images of CP that you will no doubt be subject to.
With your background you shouldnt have too much trouble with any questions you get relating to the technology.
Best of luck with the interview and if you get the job don't forget to do what our tech does, when you can sit with an examiner, watch and ask questions. No body will mind if you show your keen and want to learn.
Good luck again.