An old one to you chaps but a new one to me !, 1972 - 1.7 won't idle - misses on acceleration and is lumpy! Options

[Bibble]

Hello all, apologies for opening up as a new member with an old query - but can't seem to find the right combination in previous posts to guide me in resolving my poor running.
I bought a 1.7 very recently - it was one of two demonstrators used by Porsche in the uk in the early 70s it's registered in the uk in 72. It has covered round 73000 miles and less than 500 in the last three years it seems. It has good history and well looked after it appears original paint clean and all original. The car starts ok - it has its original injection system. It had an mot ( road test once a year ) until November next year. It feels a bit flat but lively in fits and starts - 'missing 'as you accelerate that bit harder. I'm putting some of that down to not being driven any distance for a long time. The real pain is that once warm or even warmed up a little it will just die as you approach a junction. I'm a bit unfamiliar with left hand drive the strange handbrake action (getting the hang of that now!) and the dogleg gearbox - trying to keep the engine from during and cope with the other new techniques required has been a little entertaining ! I hope that with just driving and driving a bit harder the engine might run better as it gets used, but the cutting out needs sorting. I have read on the forum and in the manual the richness of the fuel can be an issue at idle, and the exhaust is quite dark and sooty - but all advice seems to be dont try and adjust it without the correct analyser. Is that my next port of call - the garage and an analyser .... The car does restart ok ish .... Each time it cuts out but you have to give it plenty of throttle. Any thoughts much appreciated and very pleased to have found such a lively forum ! Best wishes. Jonathan