Good luck with the insurance company. I'm having a discussion at the moment with mine as they want to use second hand and non genuine parts on my daily drive. They don't care that I don't (and never will) use/fit second hand and after markets parts.

The assessor told me that they will repair my car as cheaply as possible. Pity that their premiums aren't as cheap. When I questioned the insurer on why my premiums were so high for my daily drive they sprouted about the cost of parts etc, then when I make a claim they choose the cheapest option for them.

My advice is to write to them and see what happens if they can't find replacements.