We had solar panels installed on our SW facing roof 18 months ago at a cost of just under £6k (for 16 panels) We sell back to the grid at just under 18p and have seen some great quarterly returns. My prediction is that if the returns each quarter remain as they have been, we will make our initial investment back in approx 5 years. Having no plans to move this suits us fine.
Our old electricity bills were £110 per month, so we were unfortunately high energy users due to huge pumps and filter systems in our koi pond. Dependent on the season and light levels we now save anywhere between £50-£90 per month on our previous bills.
We did not purchase a storage facility for the electric we produce at the time as they are still relatively new, and the prices extortionate. We will invest in one at some time in the future though.
I would never recommend solar panels to someone who does not have a high energy bill, it just wouldn't be financially sound. My mother only spends £35 per month on electric, and after getting the costings for installation etc, we decided she would be better leaving her money where it is.
When I was looking into having panels, I found very little information available which was of any particular use. So I knocked on doors of people who had them installed locally, gaining as much advice and information as possible. Then I got a local company out to give a quote, within a week I had paid my deposit and booked an installation date.
I hope this information helps in some way to your decision as to invest in panels or not and if they are right for you.