Bikes in Europe - Insurance

Kal and Tim

Hi all, we are in the process of purchasing 2 electric bikes to take to Europe with us on the back of our Motorhome. Does anyone know anywhere that provides insurance for them for more than 90 days continuous?  We have tried a few but from what we have found
you have to return either after 30 or 45 days in Europe and we are hoping to spend up to six months away.  Many thanks, Karen