Leave those meter seals intact
The cables from the cut out to the meter are not ours to play with
As flukey,the 25mm tails in the consumer unit can be jointed to whatever is existing,even if they are well undersized 6mm or such
The supplier can be notified to come and make that connection,it used to be £16.
They can then replace the cut out seal (that was removed for safety) at the same time if they want,or not,its their choice, their equipment, their responsibility
If they dont fit the new tails its not your problem, if the meter gets cooked, as long as the connection was requested the problem is theirs