That's a bit annoying! I am on a fixed rate for a year, well I'd say it's up now since end Jan but while it was fixed when I took it if the price decreased (which of course it didn't ) they would honour that too.
I kicked up last year over an increase in the tank rental and they advised me ring my local rep to see if there was anything he could do, I had never heard of him or had any dealings with him since I went to Flogas. Anyway he offered a one year contrace with a reduced rental and the fixed rate offer so I went with it.
How much are you using in the year? This really annoys me about both suppliers that they increase your unit price if you are not using enough. I got a phone call last year from some company doing a survey for Flogas, I explained I thought it was very wrong to be doing this, 2020/21 we had Covid and war and Leo telling us conserve energy and when I did that like a good little citizen (for the benefit of my own costs too obviously) all I got was the price increased by Flogas so I would have been better off keeping my heat on longer and using more gas than trying to reduce. It's a mad system. It's not like I cost them anymore than a bigger user, in fact less as I just take usually one delivery about every 10 months, should start costing them more by ordering couple of hundred quids worth every time instead!