Midgets/sprites are well catered for in Practical classics magazine.
If its been lying about for a while check all the brakes and lever the clutch arm back and forward to make sure they cylinders haven't failed due to something else.
Engine is easy to tune (Will either be the A series as in Minis and Metros or the Triumph 1500 used in the Spitfire, Herals, Dolomite etc.) and parts genuinely cost buttons!
If you have to weld the sills or floor do it with the doors shut, if you don't you will never get them to shut!
Pretty sure Practical performance car had a Midget with an MGF?Lotus K series engine if you are feeling ambitious?