Ok - lesson learnt, make sure your K8s version is correct before upgrading, doing it after you could end up with a bit of a mess... What I've found is that the rollback works fine - rancher is now running on the previous version, however the cluster upgrade no appears stuck on "removing" I went to the Upgrade controller, plans and deleted the two upgrade plans since the version I chose for k8s wasn't compatible with the rolled-back version of rancher - since it hadn't appeared to start I assumed it would be safe to abort... Now it might be ok - however its been about an hour and still says "removing" ... 1.32 not 2.10 compatible and was the version I'd ran to update to during the attempt to update to 2.11 - if I can get past this my plan is to update to a version both support before updating! Question is - do I wait this out? Or does something need kicking?

OK - spotted finalisers were present - so manually removed those from these jobs -

finalizers:
    - systemcharts.cattle.io/rancher-managed-plan

Then they reappeared as active plans again! The concern is that this k8s version isn't compatible with 2.10, hence trying to stop this progressing... the nodes in this cluster don't appear to be updating yet - no sign of draining etc, so should be possible to stop this...

Deleting the plan it just gets recreated... So currently Rancher is trying to update the local cluster to 1.32, that version isn't on the support Matrix, I can't stop the upgrade - I can now delete thrm from the plans (Cluster->local->More resources->Upgrade Controller->Plans) however the upgrade immediately appears in the list again (i think because I removed the finalizer, though begs the question - if it was deleted how did the changes persist?

I did backup first anyway so will look at running the restore next!

Right - restore done, now begins the upgrade in a better order!