There was were 2 extra 757 flights to ACE and TFS in April for the school holidays, but no other 757 from TCX this month.
TCX have had a really bad start to the summer. Mainly due to 4 aircraft being grounded at some point over the past few months because of damage caused by ground equipment, nothing to do with the "Ex MYT A320's being unreliable". Every aircraft and airline has its share of tech problems.
Also TCX is awaiting delivery of a new A321 from Turkey which is late being delivered, which replaces G-SMTJ thats now in Scandinavia, hence the Neos flights this weekend.
The extra DLM 955K is for the bank holiday, not sure if its also school holidays again? The other 2 are normal schedules.