Some insurers are age limited. If you stay with one company, they may keep you in but there may be insurers that will turn you down at a set age. Davids age is becoming higher risk so i would also just take up the offer.
I have found my travel insurance, once i got to 70, more than doubled and about 1400 pounds for 2 Worldwide with a couple of medical problems.
My bike insurance used to be unlimited mileage and was going up steadily each year so i restricted it to what i actually do.
I anticipate i will pay around 120 next year for 3 bikes comprehensive locked in a fortress overnight and never left outside in the road.
Carole Nash might be worth a punt just to compare but these days they are asking if you carry pillions. I dont carry pillions now but i still have pillion cover just in case a Grandchild wants a ride