I'm familiar with the sad demise of CTUK, a severe blow to the overall diversity of the industry, (not to mention the individuals directly impacted by the closure). However, I didn't realise all CTUK staff were employed.
But getting back to your wondering if worker status could apply to cycle Instructors, the answer is, absolutely yes! Three years ago when some of us first met with IWGB, they were pretty adamant that worker status would apply to instructors. Not only that, they were pretty keen on going for it, through the courts. But there was a problem, about ⅔ of Instructors at that time wanted to be self-employed, or didn't want to take the likely hit to their hourly rate l, inevitable with worker status. The other ⅓ were a mixture in favour of worker/employed status. Ultimately, that's why we went down the association route rather than the union route. Academic because it came to nothing at that time.
Personally, I think a better balance of all three employment status would be best for Instructors and the industry, but the question remains: what do instructors want now?