Engine juddering, spermatic start

Never heard of " SPERMATIC START " Exactly what is the problem , is the car fixed or not ?

It was meant to say sporadic. No it’s not fixed, it’s not clear what’s wrong.

Is it still overheating and engine running but juddering ?

It is, there is no physical sign of any leeks, it’s been to two garages and both have said nothing shows on diagnostics which they have said could be something more serious. Both have told me to get rid of the car, but it’s strange and I don’t really want to let it go. It’s done 50300 miles, Iv taken care of it, it’s just past a full service in may, so I’m confused!
The engine will some times turn on and run for a bit then start to judder and shut down, or it just won’t start, it will judder and judder and cut out. So there is no warning or frequent pattern to switching of. I wondered if it was a known fault but I can’t see it anywhere and I don’t want to pay another garage (Vauxhall) to tell me they can’t find anything. Iv had the car from almost new in 2017.

With the problem with overheating it may have caused more trouble than replacing the coolant header tank .is supposed to have fixed . You could have cylinder head gasket fault which causes pressurising of the cooling system and one of the results is often the damage to the tank . But that is only minor as serious internal damage can occur to cyl . head / gasket causing engine to run rough . A simple block test will confirm or refute this suggestion.

Thankyou so much for your reply!! I am I right in thinking I can do the block test myself after looking online or would you recommend I went to a garage ?

You can do it yourself after buying test kit , simple test .