JP, I think the issue isn't that it isn't the right tanker, rather that PPI is not, and never has been the bargain it was cracked up to be. Hence the RAAF scorning it and the FAF eliminating as a possibility.
the fact is it was just a method of shifting debt off balance sheet and avoiding showing how much we owe, and have ourselves in hock to in the future.
The present government has promised to come clean and reveal all the true figures, including PPI ( and I hope civil service unfunded pensions etc).
If they do that, and assuming the contract has a get out clause, it may be more effective to switch it to a straightforward purchase.