Hi,
I am also a level 2 plumber, was made redundant 2 years ago from a company who fitted basic bathrooms and kitchens.
Went on my own just plumbing and bathroom fitting.
Best thing i ever done! just got out there and went for it. Have learnt so much in two years and really enjoying the freedom of being on my own.Just have to be confident about your own ability and be as flexible and friendly with customers as you can.
Sure you will get the odd job that is a bit beyond what you are used to doing but there is so much access to advice out there from manufacturers and internet, if you get stuck just research as much as you can . If it really is too much then walk away from the job and stick to what you know nut the best way of learning is to go for it.
It is a bit scary at first but you dont rely on getting employed because nobody is taking people on at the moment, and any that are are paying peanuts! Fine if you are on your own maybe but not with a mortgage and kids!!
Just keep working as you are and it will get better if you do a good job and dont try and caharge the earth.
good luck