FWIW, we have a 6.25 kWp array, facing slightly west of south, inclined at 45 deg. I can count the days on one hand where we've generated more than about 3 kWp at any time, and the total generation so far since the beginning of December is about 200 kWh, so around 4.2 kWh/day, although there have been lots of days when we've generated next to nothing, which is pretty normal for this time of the year.
I was curious of your thoughts on this recent collaboration between 6 different american ICF companies. What window sealing strategy would you use below....see the the link the picture for the answers
Here's the short report.
Using PVGIS and assuming azimuths of 100° (10° North of West) and -80° (10° S of E) gives 48.5 kWh and 59.9 kWh for December and January respectively so your 50 kWh/month looks pretty reasonable. That's for a point at the southern end of the main runway at Sutton Bank (Yorkshire Gliding Club) which will have a pretty clear horizon from east round through south to west.
It seems to me that 1.5 kW would be a bit optimistic with the low sun and the awkward angle on to the panels. Still, 200 W does sound a bit disappointing.
(Does the “T21” in your name have any gliding significance?)