Hi Lewis,
I think that having done this once it must be harder second time around, but there are lots of people on the forum who are very successfully doing it.
My head really had to be in the right place to start this. I've lost large amounts several times in my life, and I've also had numerous false starts when I wasn't really ready to make the changes.
Only you can know if you are ready to stick to this and get to your goals. If you do start you will be sure to get lots of support from everyone on here.