Sinclair Computers - ZX81 and ZX Spectrum

It must be an age thing but I’ve recently started (investing?) in retro kit, from the 1990s, 1980s and earlier. This has included hifi (including recently a superb Pioneer A400 – http://www.gbaudio.co.uk/data/a400.htm) amplifier, and vinyl LPs, but one item that I’ve had on the list for a while is a Sinclair ZX81 home computer. I bought…