NEVER go with your car insurance renewal.
We recently got our multicover renewal through, which was by far the cheapest last year. This year, they whacked an extra £250 on the price, out of no were. Ridiculous.
After doing a little price comparison online, I rang them up and straight away they knocked nearly £200 off the price, within 2 minutes of me being on the phone.
It was still more expensive than the two separate quotes I had in front of me (for car & van insurance individually) so I went with the cheapest, which actually worked out, combined, as cheaper than last year. Over £300 cheaper than my original renewal quote.
I think places like this should take note. You might get away with a couple of people accepting the renewal, or just letting the automatic renewal continue year on year, but you’ll likely lose customers by trying it on in this manner.

