I too have suffered a lot over the years with Cholesteatoma. I'm up in Belfast, and go to the Royal Victoria Hospital. I'm scheduled to go back towards the end of April.
Headaches and earaches? Have you had, or do you have any pain or inflammation at the back of the ear (Mastoiditis)? Hearing loss or dulled hearing? Smelly discharge from the ear? Dizziness? Are you getting any treatment for the pain (painlkillers)? Are you on ear drops and/or antibiotics?
Judging by what I'm reading from you, I would go back to the ENT unit and tell them of your concerns. If you think your Cholesteatoma has returned, TELL THEM. In my own experience, Cholesteatoma can be notoriously difficult to diagnose and they might not even consider it unless you mention it to them. That's what happened with me.
With my last bout in my left ear last year, I had to literally fight with my GP to send me to the hospital, and had to fight with the hospital to look at me. I had it before, and knew deep down it had returned, and I said as much to my doctor, and to the registrars once I finally got an appointment.
But if what you're suffering from was happening to me, I would INSIST upon a CT scan. They may want to "look at other avenues" first - let them, because if effective treatment works, that may well rule out C-toma. They will want to rule it out before, shall we say, ruling it in. If treatment doesn't work, then at that point, they may send you for a CT scan.
Give me a shout if there is anything else you're concerned about. If I don't know, I can ask my consultant when I see him again hopefully next month.
Below is a link to cholesteatoma.net where you can see my posts of the struggles I have had with this. Feel free to add me on facebook if you want to, though make sure you send a message and mention Cholesteatoma, as I don't otherwise add people unless I know them directly.
Let me know what happens, and good luck.