I'm a marketing manager for an insurance company, and it's incredibly interesting how it all works. Here's some general advice from my 8 years experience in the industry:
1. Some people may be able to get cheaper by calling, but 99% will not. The reality is, its cheaper for insurance companies to set up policies online, so most companies will always put their best deal through this channel. They don't actually want you to phone in as this costs them
resource time and money. Also, 80% of insurance companies you speak to are not the insurer, but just a broker for the product (Asda, Kwik Fit and Pets at Home, do not know
how to write and administer insurance!). The price is set by the insurer, this means that the person you're speaking to has no influence over the price. That being said, they may be able to
help you flex it by changing the level of cover or what add on's you have included.
2. If you do want to call and talk to someone, my advice is call as early in the day as you can (also better earlier in the month). Typically sales teams have targets of volume (number of policies sold) not money. Volume is key in insurance as this opens up the door to cross-sell (add on's and other insurance products like home insurance), this is where insurers really make their money. Because of this you're far more likely to catch a call handler willing to work hard and
help you find the right price if they haven't hit their target yet.
3. As everyone knows, insurance costs are based on your 'risk profile', but who is cheapest to buy from is based on each individual insurance underwriters appetite to risk. You need to find the insurance product which best suits your profile. As a company which is cheap for you, won't be cheap for someone else. There is no such thing as a 'cheap insurer'.
Love them or hate them, the best way to do this is the aggregators (price comparison sites). Aggregators have come such a long way in the last 7years that they're now better at matching you to a relevant product than the insurers are (we now go to the aggregators to learn about our own customers!).
My best advice for finding the best price is this:
The aggregators, but not just one. Each aggregator has a slightly different panel of insurers, so you should try a few of them. Try 3 or 4 aggregators and get the cheapest price from each, then phone Aviva and Direct Line (who aren't on aggs and only deal direct). Tell them you've already done the price comparison and wanted to see if they could better it.
Then just go with the cheapest you've found. Once you have done that, I pretty much guarantee you will not be able to find a better price for yourself.
Hope that helps people out?