Company Car Petrol Allowance

There's also the issue that most people aren't insured for business travel.

This often costs about £5 extra so I don't think this is a genuine objection if you are being properly compensation.

This means nothing to companies and they're just trying to make their lives easier at your expense.

Obviously any business will try to make their lives easier.
Personally I don't think it's at my expense because 40p per mile more than compensates for the costs (unless you drive a real gas guzzler).

I agree that you should have the choice, but I don't agree that it's a big negative.
We find having an extra car a real pain because we have nowhere to park it and end up shuffling cars round especially if we have to keep it over a weekend. Also you often have to fill them up so additional trips to petrol stations.

I would personally rather use my own and keep the profit, but entirely up to you.
If you run a modest car then the profit can be good.