Maybe I'm missing something here, and I'm interested to understand what it is - why is something like TUPE relevant?
The employees are employed by Company A, Company A had a contract to provide a service. Company A has lost the contract, Company B won it. Company B has not taken over Company A, or a subsidiary of Company A, so why should it have to have anything to do with the staff of Company A? Are the employees somehow tied to the contract?
I know in my industry (Software), when we win or lose a contract we don't transfer to our rivals (or have them transfer to us) - even where you might have been full time engaged on the contract.
If there is some sort of obligation, why doesn't for example the rivals who beat SR Technics to 3 out of the 4 Aer Lingus contracts that were up for renewal earlier in the year take on the SR Technics employees? I know they are in another country, but based on some of the comments here should they have been offered jobs etc?
I would have thought Company B can choose to hire no one, any or all of the employees of Company B, completely at their own discretion after their own recruitment procedure, with employment terms & conditions they deem appropriate, taking NO account of existing seniority, T & C's etc.