Time for a new office chair

Following a spinal operation I have been having several issues with sitting down for long periods of time and with me working behind a screen and desk for most of my time its becoming more and more difficult to stop my back from stiffening up. I seem to have a substantial amount of scar tissue which restricts the movement in my lower spine.

Anyway, the point I am getting to is my posture at work. I sit behind a desk for a good eight hours a day and despite being told by the osteopath and physio to get up and walk about every hour when you are busy its difficult. I have been looking into the office chairs that we have in the office and wondered if it would be worth buying something like a Gull Wing Chair which has a bit more back support than your standard office chair.  When I first came out of hospital I was looking at ergonomic office chairs but the price of them put me off, however, two years later they have come down in price so I may just have a look at those too.