[waterbuffalofarmer]

cOuld someone tell me how solar pv works and how much does it save on electricity?

I'm certainly not an expert, but basically:
Solar PV panels convert sunlight into electric, which goes through an inverter panel that is linked up to your electricity network. If you think of it as water, when your panels are generating the electric, the 'pressure' on your side of the meter box is higher than the local grid network so any excess electric you might have (after your own electric needs are met by the generated electric power) is output to the global grid. If you aren't generating excess then your electric needs are met, as usual, from your electricity supplier.
The savings are made in 2 ways - your inverter keeps a record of ALL the electricity to generate via a meter. You are then paid an FIT rate from your FIT provider (generally your electricity supplier). You get paid for a) total generation and b) an assumed amount of 50% of your total that is considered to be exported.
In addition, when your panels are generating, you obviously meet your own electricity requirements from your own panels, therefore you don't demand so much from your supplier so your bill is less.
However, the panels only generate during the day when the sun is out (doh!) and if your elec needs are low during the day (eg no-one at home during the day) then you won't benefit so much from your own generation and your elec bill won't go down as much as your majority use would be in the evening/night when the sun's not out anyway.
There are intelligent switches that can be used to switch on immersions etc when the generation is enough so that you use more of your generation and you can have a lot of fun (?) trying to work out ways to maximise this.
Are you confused yet??? 

I understood it perfectly, very well put if I must say so! Thanks

[Greenerlife]

80 units for January.  Down from 109 last year 

[Big Light]

39.7 January - less than half of last year

[Sudanpan]

117 for January - we got 130 in Jan 2015.
Considering we only generated 52 in Dec it shows Jan's weather has been a bit better - but our ground is just sooooo wet I am looking forward to a bit more sun to dry everything out

[Big Light]

165 for February around the same as last year

[Greenerlife]

175 in Feb up from 129 last year 

[Sudanpan]

181 for Feb - Feb 2015 was 229

[Greenerlife]

298 for March - almost exactly the same as last year.

[Sudanpan]

434 for March - last March was 432

[Big Light]

 276 a reasonable month for this time of year

[Dan]

301 in 2016 vs 300 in 2015. A good month. 

[cloddopper]

I did a two month comparison ,for Feb & March last year against this year surprise,  416.08  total for FEB & MAR last year,  this year 442.20 .

 That's 26.12 more units for this two month period .

[cloddopper]

Been away , got back last night,  todays 3 May reading is 7697.98 units on the meter , that gives us  3 more units that last year for the month of April till the 3 May 2015 .

 I think getting the panels professionally cleaned by our window cleaner , ( I can't do it anymore ) with de ionised water has helped , but it has reduced our earnings from the panels by £ 40 .

[Sudanpan]

606 for April 2016 vs
747 April 2015

[Greenerlife]

489 for April.  Much better than I expected.  10% up on last year in fact!