This is something that regularly happened to me in over 40 years of Caterham ownership and why I built and/or owned 15 or 16 Caterhams in that time. Every time I started getting bored and not using the car, I sold it and ordered another car, usually a kit to built, with more power or other improvements, and found I was then using it to its' fullest extent again for 2 or 3 years.
I bought my ARP4 in spring 2016 too, with a history similar to yours Perry (but without the Porsche input) and this year I cannot have done more than 200 miles, in fact it has sat in the garage since August, untouched and practically unloved. I am contemplating putting it in an online auction and getting an Alpine A110 or maybe a 911 Cab. I just don't want to pull the trigger on getting rid of it yet, so may wait until the spring and re-evaluate the whole thing.
So I think it must be a normal reaction, thank goodness I haven't done the same with my wife, after 50 years together, it may not be quite so easy to move on!
