Talk

WOULD Speak too Adoption team and social worker soonest, may be a little too late, but be best for yourselves too express your best interest for the children .and their outcomes with least disruption., as the children have been placed for more than a year you can apply for adoption in your own right direct too Courts.
Would ask advice from CORUM Legal and first4Adoption.

Is this your first newborn and small child placement?

it is usual to not want them to leave, but is staying with you really best for them?

You would be breaking up a family, parents who are waiting excitedly for their children to come home to them.

Our job is to foster and help build new families, not keep the children for ourselves.

I know some children just click and foster carers adopting them is right, but not as a knee jerk reaction to them leaving.

Think really hard as to why you would want to keep them, and if you proceed make sure it is for the right reasons.

you would likely have to give up fostering and wouldn't get financial help, or very little financial help.

You have obviously given these two a wonderful start, enabling them to go on and be part of their forever family, you could do that again for other children, making something wonderful happen again with your care and compassion.