I've never bought a car from these people, but have negotiated with others trying to charge similar fees. I find that if you really push it they will give way.
After negotiating all your worth, tell them the £98.99 package is a deal breaker and see what happens. Do not be afraid to walk away, bet you get a 'phonecall in about 2 days.
Must admit I never needed drive away insurance, just 'phoned my insurance company to change the cover 5 minutes before I drove it away.