Hi, thanks for the reply. I have had the bike for about 3 months now and have been riding it nearly every day, or at least every other day. I sometimes ride it twice a day if I have time and each session is around 30-60 minutes on a low resistance (it goes from 1 to 8 and I use 4). I haven't gotten any sores or blisters, the pain and numbness seems to be more internal than anything else and seems to originate more from my sit bones. I have recently started getting a shooting pain that starts in my lower back and moves down my right leg. It happens very randomly but I don't think this is because of the bike per se, more to do with my pre-existing back issues and my supposedly firm mattress which just doesn't give me enough support really when I am in bed.
I am going to ease off the bike riding and see if my shooting pain subsides as perhaps the cycling may be exacerbating it a little.
As for the seat, on my bike it is fairly easy to change as it has a clamp with two nuts either side to attach it to the post so I can just undo those with a spanner and swap seats in and out and adjust them as necessary.
I think one of the biggest issues is that riding a stationary bike is not really like riding an actual bike outdoors. You spend nearly all of your time sat in one static position on a flat surface, whereas outside you would have the different road surfaces and gradients and are able to move around a lot more and even stand up riding (I have tried this on my bike but it just doesn't feel comfortable or stable). I do get off the bike every so often when I start to feel some discomfort and have a break for a minute which does help but I think overall I probably just need to find a seat that suits me more.