The cheaper insurers do seem to add admin or other charges at every opportunity, don't know if the one you are with is one of those mind.

Maybe an email to ABI detailing the problem might bear fruit for you.

Wifes Kia Ceed SW "3" has 225 45 17 as standard. For winter we use 205 55 16 as fitted to the "2" model on Kia alloy wheels. No additional charge.

My Seat Leon uses 20 55 16 as standard. For this winter I have bought 4 genuine VAG steel wheels and will use 205 55 16 tyres on them. No additional charge.

Both with Aviva.

You have gone for a smaller size wheel, with a more standard profile. Ask again about the insurance, I was not charged extra to change from 215/50/17 to 205/60/16 wheels / tyres - crucially these are also a standard fit to my car and I have used original Nissan alloys. (Thanks ebay and breakers yards)

A second consideration is the possible lower cost of tyres for the smaller size wheel, it may even be a greater saving than the extra premuim.

That's a good point about the tyre costs - I'll have to check again how it all adds up.

I've tried twice with the broker so far. To their credit, they have talked to the underwriters but couldn't get anywhere. I've written to the underwriters directly so I don't think that there is much else I can do until renewal time next year.

If the underwriters bother replying I'll let people know what they say.