The TCX flight is operating the PMI service for the first 2-3 weeks I believe using an CWL based crew.
Secondly - staff shortages. Something that has been a problem at MME for a number of years but has never previously been so bad as to force so many closures. The problem I believe is that there is still at least one controller on long term sick, and of course SCRATCOH dictates you must have at least a 30 minute break per 2 hours. Since there doesn't seem to be enough controllers to run 3 morning and 3 afternoon shifts (1 for radar, 1 for tower and 1 on a break), I have heard they are currently running 2 mornings, 2 afternoons and 1 day shift which would explain the times of the closures.
If it continues, I can see GSM in particular being rather put off and I don't see why they would want to come back next year. If only upper management at the airport had took a grip on this situation several years ago and paid the going rate for ATCOs and MME may not find themselves in this mess right now.
Rumour also has it that SRG are not happy about the current situation and are visiting management at MME in the near future.....