As far as I understand, although I stand to be corrected:
Flights from BOH, CVT and DSA are 'traditional' loco scheduled routes.
Nearly all other flights are seat only's on normal charter routes. However I think a limited amount of flights from Gatwick, Luton, Manchester and Cardiff are also lo-cost only. The Thomsonfly website states
The flights shown on this web-site are ATOL Protected by the Civil Aviation Authority. Should you purchase a flight departing from Bournemouth, Cardiff, Coventry, Doncaster, Gatwick, Luton or Manchester, such sale will not be covered by ATOL protection, unless specifically referred to within the booking process.
So LGW/LTN/MAN and CWL must be a mixture. confused?