The main problem with insurance is that underwriters look at the amount of business they hold and the risks that they are taking. If they have to much risk they up the premiums so they shed customers. If they want more custom they reduce the premiums.
Premiums are calculated each month, so if you renew this month you may pay more than if you renew next month, but of course this can be in reverse as well. What you need to do, although it is a bit time consuming is to get as many quotes as you can, but ensure that the cover and policy conditions are the same. i.e some have a high voluntary excess some don't. Some give you the third party extension to ride other bikes and some don't. Some with not cover theft after 10pm to 7am unless it is garaged. They will not pay if the keys are on or in the vehicle if stolen to give a few examples
Please always read the schedule of cover as all to often you think that you are covered for a risk then after an accident or claims it turns out that you are not and the insurance company likes nothing better than to walk away saying " in was in the schedule of cover".
Hope that helps....