I finally got through to the Energy Saving Trust in Edinburgh. The lady I spoke to said there were quite a few applications in before mine so news about my loan for installing solar panels is not imminent. I did mention to her that I was in a queue with Installation Company with 2 to 3 weeks remaining. Her suggestion was that I hold off postponing the job until a week or so before it happens and if I haven't heard anything by then, give them a phone.
In truth, I don't have a definite date for the installation. My only clue came from a conversation with an employee of Installation Company who I spoke to on Easter Sunday and who said about 4 weeks. That put it at the beginning of May.