My husband had PD. He made the diagnosis himself as he was a GP.
You need a proper diagnosis first. I would go private if I were you - my brother, who also has PD, did this then transferred to NHS for ongoing treatment. The sooner the diagnosis is established, the sooner treatment can be started.
PD affects people very differently. My brother has responded well to the meds - although, as always, there is a bit of jiggling around needed to start with to get the dose right. My OH did not respond so well and we had to deal with lots of side effects and lots of changes of meds. You need to be aware that the meds can cause strange side effects and that you need to feed these back so the right mix can be achieved.
I would recommend Parkinsons UK - www.parkinsons.org.uk - they have masses of information, a phone line and supportive help. They sometimes have local groups as well.
Locally we had a brilliant Parkinsons nurse, who was always at the end of a phone or an email, and who was able to change the meds without going back to the doctors. It was such a wonderful support to us all. When the diagnosis is established make sure you ask for this contact.
There are neuro-physios who can help with exercises to keep patients active; and the whole battalion of OTs who deal with equipment for the home etc. Take everything you can so as to make life easier.
As you might have already worked out my OH died - but not of PD itself - he died because, 13 years after diagnosis, he fell and fractured his hip and this proved to be more than his body could cope with. He lived for nearly a year after this but his care needs were very high during that time. People do not die of PD, they die with it.
It is very important to avoid falls as people with PD find it harder to recover from these, especially if a fracture is involved, so do make use of the falls prevention clinic - most hospitals have these.
Keeping mentally stimulated and interested on life is also very important. Sadly my OH lost interest and motivation, so this was challenging; but my brother is determined to wring everything possible out of life while he can and plays golf, goes to the theatre and generally stays plugged in to life.
If I can be of any help please contact me.