This is not permitted by the rules. Feeding in more bases by expanding is not compulory. Feeding in bases is not an exception to the rule about rectangular formations, so cannot be done in this example.
The rule is a little odd. If the knights had lost a base in the impact combat, they could have expanded the base becaue the 2,1 formation would be legal.
It would be nice to have my opinion confirmed before I have to argue the case in a competition.



