Now it would appear that the above link can be relied upon , its exactly what i was told by the nutty proffesor type guy in the electrical shop i first went in , as little as 1 hour of usable sun on a winter day , this guy has had the same shop in my town for at least 30 years !
I think he is past the sell anything to anybody point , he is there purely to sell people what they need , i trust him .
He told me from the outset that i would need 100w for summer and 200w in the winter to stand a chance of being off grid so to speak .
I have been taking the battery out for 12 years daily , so i can carry on .
For me its more of an access issue lately , parking at my house is getting mental , i used to fill up easy , these days im up to 30m of layflat just to fill up , i have even been forced into having static systems at the front and back of my house , 800 IBC at the front and 450 tank at the back !