DC3 Dave
Don't assume anything with SARG. You mention SEN issues, which are/were Aerodrome Licensing related. SARG is comprised of a number of different entities.
The apparent CAX ATC issues are governed by their Air Navigation Service Provider (ANSP) Certification, which is a whole different rule book (s) from CAP 168, overseen by SARG's ATS regulators, albeit part of the Airspace, ATM and Aerodromes section.
Broadly speaking the ANSP Certification requirements are far more complex than Aerodrome Licensing when it comes to staffing, which appears to be at least a part of the delay caused to commencement of scheduled air transport flights. The requirements include ATCO licensing, training and working hours regulation. In many respects the scope for flexibility is minimal. Put together with the current shortage of UK ATCOs,,unless CAX has by now recruited them (or are "leasing" them, to use a long term marketing pitch of a UK company) even the delayed target operational date for scheduled services may not be achievable.
In the absence of any further fully qualified ATCOs I would speculate that with only three ATCOs in situ, assuming that all are ADI/APP rated and hold Unit Endorsements, you are possibly looking at a five day week operation with restricted operating hours (not good for delayed flights) or the likelihood of some non ATC availability during the day while duty breaks are taken. That's assuming nobody calls in sick or wants leave!