Many thanks for your patience. You are correct that there is a law on taking employees over in the event that you take over a business. This is under the Transfer of Undertakings (Protection of Employment) Regulations 2006 (better known as TUPE). It is implemented as domestic law, so it will remain unchanged after Brexit, unless the Government specifically tries to remove it in the future but I doubt that would happen for a few years, if at all.
You could indeed discuss with ABC to make some of its employees redundant before the transfer and they can easily pick out those with less than 2 years service as they have no unfair dismissal protection anyway.
If you do take over some of their staff but do not need as many, then again you can select those with less than 2 years service for dismissal as they won’t be able to challenge that. Anyone else would have to be treated fairly and you have to place them on par with your existing employees, so you have to go through a formal redundancy procedure with them and treat all employees equally, which means potentially making some of your existing workforce redundant if they perform worst in the selection exercise.
Finally, you have a duty to honour the incoming staff’s current contracts and that is another requirement under TUPE. You cannot just use the excuse of harmonisation to try and change them
As to your own position, you are just as vulnerable as anyone else with less than 2 years’ service – you can be dismissed quite easily so you will have that hanging oiver you for at least another 6 months unfortunately.
Does this answer your query?