I had my system installed in Nov 2014, It was £7,900 then but we went for a more expensive system because we have a roof that has multiple angles and we needed 'micro-inverters' to maximise the yeald. I dont know the market but I should expect with a single 'string-inverter' you would get a similar size system for half the cost today.
Feed-in-Tarriffs wer drastically cut here, but I expect with reduced costs it still pays back on a similar timescale, mine is around 8 years.
Thanks for taking the time to reply @scalextrix, really appreciate it. I'll take another look at the possibility of getting a system installed - that's actually cheaper than I expected for a reasonable system. I'm sure I remember looking at it some years ago and the price was astronomical!
If you do get a system, dont forget to claim your free SolarCoin www.solarcoin.org