Hi Delboy1960 and welcome!!
In answer to your question, it's difficult and certainly not an easy ride. I've been going for 3 years and in the last 6 months or so I've had plenty of work but after my first 6 months (when I had plenty of work too) I just had to be patient. Few customers, one or two weeks with no customers and so on.
The attitude I took was my course was the driving test and I would then have to spend ages learning on the job. For example, they don't teach you how to undo a jammed stop tap. Of the 8 on my course, I think I'm the only one who's been successful in working for myself and making profits. Just about all the others went back to previous careers.
I've found there's a world of difference in fixing old peoples' WCs and taps and replumbing a house renovation. The first jobs are quite easy to find and will pay around £50 a trip. The replumbing/new heating day rates for several days or a month or so of work are much more difficult to secure and I've yet to replumb a house off my own back. (I've been lucky to meet an experienced plumber and help him with these jobs.) These latter jobs are what really pull the money in, but until you get a name for yourself, they're essentially non existent.
I also found this last winter did not earn me huge amounts. I was out everyday and had plenty of emergencies but when it's an older lady who's got a burst pipe I haven't the heart to write out a large invoice as she's gone through enough trauma already.
As with any small business, you make your own success and it's hard work if you're going to be successful. I'm not saying you can't do it, but hope that I've indicated that work doesn't just come to you and when there is a job, there's not a huge amount of money involved.
My situation this year is I've been out everyday and been really busy. Next week is all booked up but after that I've no idea what work there is as the phone hasn't rung for a good week or two.
regards turnpin and good luck