I have a grid-tied inverter on a nominal 1.7kW system. For the last 6 years, I have been logging the generation meter pulses (1 pulse per Wh). While this has not been without hiccups, I have enough data to be able to generate the mean annual generation plot shown. This gives, for each day of the year and each 15 minute interval, the mean power generated by the array and delivered to the grid (i.e. subtracting the inverter losses). The colour scale shown is in kW. Overlaid on this plot is the position of the sun at every moment, in the form of a double contour plot. The green contour lines are elevation, the purple lines azimuth.
This shows up the shading which limits the afternoon/evening performance of the array, and the surprising* variability of the weather, even in the summer. Also, how dire the winter performance is at this latitude!
From the sun contour plots, you should be able to work out roughly where this array is located...
*Only really surprising to people who don't live in the UK.