That's what I did after my dc started school.
I found an organisation called Women's Farm & Garden Association. They run a scheme called 'Work and Retrain as a Gardener' or 'WRAGS' for short and link up trainees with their partner gardens. You pay a fee for getting on the scheme (much cheaper than paying for a training course!), and then get paid while working at the garden.
You need to commit to two days a week for a year. Lots of people do an RHS course in tandem.
I did my training at Arley Hall which was fantastic and did my RHS course at Reaseheath. It was a great move for me. I am now self employed and fully booked!
I have recently taken on the role of Co-ordinator for the WRAGS scheme covering Cheshire and therefore this post. We need to spread the word in this area (it's currently more south east dominant) and get more potential trainees on board.
Interested? Have a look at the website: wfga.org.uk or pm me.
Bridget