Thanks for the reply. I am using a Brooks Cambium c19 Carved which is pretty firm, it doesn't have any cushioning but does flex somewhat. It's not cutting into my thighs but I do feel the firmness of it pressing into my bottom which after a while may be causing the numbness. I try to sit towards the back but I think the saddle naturally flexes in the middle but I never feel like it is pushing on my anatomy in any way, as I said, most of the pressure seems to be centered around my sit bones.
When you suggest I try adjust the handlebars so that the U-shape points away from me and then rest my forearms on them, I can't really do this as I have to bend significantly forward to achieve this position, even with the seat as far forward as it will go and then my knee is much further forward than my pedals. Plus my forearms are nearly at right-angles when bended at the elbow. I think this causes me to adopt a racing position rather than be upright which I prefer. Unfortunately I can't adjust the height of the bars up and down, just rotate them toward or away from me as they are at a fixed height (roughly 92cm or 36 inches from the floor). I have measured my forearm and it is roughly 45cm from my elbow to my index finger and my total arm reach is approximately 74cm from shoulder to index finger.
My only methods of adjustment are seat height and moving the seat closer or further away from the handlebars. The seat height goes up in increments of around 3cm (there are holes in the post every 3cm where the pin screws in to lock it in place) so I thought by lowering the height it might take pressure off my hands but then too low and it doesn't feel right on the pedals. Again moving the saddle closer or further away didn't seems to make to much of a difference and without being able to adjust the handlebar height, may be causing me to get the seat position right but the handlebars can't compensate for that. The hand problems aren't as bad as the discomfort and numbness I get in my bottom so I would really like to solve that issue mainly.