I did some research a while back and found that broadly premiums increased by about 40% with a drink drive conviction.
I checked this by logging into Comparethemarket.com, putting in all the correct details, with no convictions, then going back and inserting a DR10 disqualification.
If you do it any other way, such as comparing what it was before you were banned, you run the risk of things have also changed that affects the quote, like different car, different postcode, how long you have been driving etc.
There are some insurance companies that will not give you insurance for 5 years with a drink drive conviction, such as NFU Mutual, even if you were with them before.