Had a chat with Installation Company about when inverters will become available and the latter half of May looks likely. Apparently, component supply problems with the manufacturer are at the root of the issue. They did suggest I get back onto the people at Energy Saving Scotland to chase up the progress of my loan.
They also pointed out that at over £300, the Sunny Beam monitoring system I was looking at is a very expensive way to go about keeping an eye on the output of the panels. Instead, they suggested I search for 'wireless energy monitor'. I did. For somewhere between £30 and £45, I could get a system that will do a decent job for me. Two systems come to light in the search. The Owl is very common. Tesco sell them. Another is by Efergy. Some of these will even connect to a computer and display their results as graphs though apparently their data structure is rather proprietary. You can't load the files into, say, Excel.
These units are meant to monitor energy usage in the home. They easy to use and install. They include a sensor that is simply clipped around the live cable to your electricity meter. This sensor is connected to a transmitter unit that sends the measurements to a receiver which displays the results. The suggestion from Installation Company is to use one of these to monitor the AC electrical output from the inverter.
On the Amazon UK page for the Owl unit, some reviewers have pointed out that the system lacks sensitivity. It will give you a reasonable idea of the bulk power flowing though the cable but it struggles to accurately respond to the change caused by, say, a 60-watt bulb being switched on. However, it looks like a fun gadget that I had not seen before and I might get one just to play with.
One thing to point out is that I don't actually need any of these toys to monitor the daily operation of the panels. The inverter will have a display, and there will be an approved meter on its output for the purpose of working out the Feed-in Tariff I am to be paid. I can gather these numbers each evening for the spreadsheet as I do now.