The simple answer is yes, you probably should but it’s more than just looking for the cheapest price. You may well do better financially, but it’s worth asking about incentives such as energy consultancy so you could reduce your consumption and save even more.
I wonder where you found your incredibly cheap business gas deal from either contacting providers directly or using a business energy comparison site? Either way, unless you search the entire sector of providers then you don’t know whether it really is the cheapest deal available. So yes, I would recommend contacting the Business Utility Hub also.
In addition to what has been said before, I would also look at the small print of your incredible deal to see whether it really is as good as you believe. Firstly, you need to compare the unit charge and also the standing charge to ensure these are lower than what you currently pay. If not, then it’s not an incredibly cheap deal.