Remove shelf from Fitted Wardrobe?

We have fitted wardrobes which have been in the house since we bought so assuming many years old, we're here 8 years, so they are older than that for sure. They have one rail and a shelf above and we would like to redesign the inside of just one but would like to DIY as don't want to spend a whole lot of cash on it. However, we're not so sure how to remove the fixed shelf, it seems to be fixed to the side panel without a bracket underneath. We now think you have to get the frame out to remove it. Has anyone else had this issue and found a way around it? Or a carpenter who can explain how it works?

If it's a white/cream faced chipboard type unit chances are that the shelf is held in place with screws through the gables(sides)and if it has a hardboard back then probably panel pins or staples through back as well.
If this is the case the only way to remove the shelf without removing the unit is to get ignorant with it. A good downward/upward blow will break the shelf,then remove screw ends with a snips and cover holes with self adhesive caps,the panel pins/staples should pull through the back and will in any case be hidden by hanging or folded clothes.If there are small shelf studs below shelf,these can be pulled out with a snips/pliers

Assuming that the screws holding the shelf are coming in from the gable ends could you saw the shelf from front to back. It will still take a degree of pressure to remove it but you might do less damage this way

How does this unit fit in with the overall layout? Is it a middle or edge unit?

The unit is most likely attached to the surrounding ones with screws or connector bolts. These may be hidden behind hinges. If you could take the unit out, you stand the best chance of doing this without destroying the cabinet. The backing board may be in two pieces, which could cause a problem with this plan, but you should be able to tell that without dismantling.

You will affect the structural integrity of the carcass by removing this shelf. If it's a good quality one, and well secured to the surrounding ones, then it should be no problem, if it's a cheap flimsy job, then you may not get away with it without additional bracing.
Leo