I have bats from each end of the spectrum from £100 - £500 and I believe there is a difference personally. You can get some amazing deals as we have seen from SD but they make there money in other ways and in some ways must make something on the gear they sell.
You could have bought a bike that would do the same job for £100 but spent £500. You could also have bought a bike for £5000 but £500 was your budget, choice, deal whatever. It's the same with bats in my opinion. You spend what you want or can afford simple really. Do you need to spend more than £200 probably not but if you do its not a problem in my view.
I could try and argue a reason why companies brand charge more but feel to some it would be a waste if my time. Some will just sticker up ready mades or have there bats made by others and claim to make them themselves these I do not get charging over £250 for example but those that have overheads, multiple workshops, employees etc in my view can charge what they like. At the end of the day if they have been around a while they have a good idea of the business they run.