I had both mine and my partners phone replaced by apple about 12 months ago my contract with EE has now ended but they won’t unlock phones as the iemi numbers are not the ones attached to the account

You might speak with advanced Apple Support on this issue to see if assistance can be provided in resolving the matter.

In principle replacement devices should carry the same activation policy as the original device.

There may be a deficiency in the database maintained by EE and you could instead escalate the matter to a higher level with the carrier.

Alternatively, you could review the terms of your contract with EE and file a dispute if indeed an unlock is warranted under the policy intent.

Yes, agree with Madra31 in principle. But I suspect (though it may not be legal) that EE have considered the replacement phones as a new agreement and re-started the account from the point where you received the new phones.