it should be pretty easy to work out what your *actual* losses are - i presume your work is self employed sessional stuff? Just work out what you earned last year, and divide it by 52. Then x it by how many weeks you'll have to have off to have and recover from your operation (s?)
Have you had to pay anything for medical appointments so far?
i would of thought whoever is representing you in the group action would be able to make an estimate for "pain and suffering", sorry i have no idea how much you could expect for that.
One thing i would say is that things always take longer than you'd expect though, so don't expect anything to happen soon. If you are having symptoms, and chemical leakage, perhaps you should consider having the implants out on hte NHS sooner rather than later? I get it's your living you'll be giving up temporarily, but you could always claim out of work benefits, or add it to your compensation claim i suppose