Insurance for Aussie driving in the UK

Hi, I am visiting family in the and have hit an unexpected problem.

They were intending to add me as a named driver on their insurance so I could borrow their cars. But their insurers - and multiple others we have tried - have said absolutely not, they can't add a driver with an Australian licence.

It seems there are other insurers that offer short-term policies, and others that claim to specialise in insuring foreign drivers. But none that do both. The best I can get as an Aussie licence holder is a 12 month policy, or a hire car for the whole time, neither of which is really an option.

This has completely taken us by surprise, and really messed up our plans. Anyone else had similar experience, and have any suggestions?