Hi
I have the same problem with my 18 plate Crossland x and owned as a pre reg car from new. My mileage was about 36500 when it started doing same as yours also goes into snail mode, you pull over turn off for a minuet or so and you set off again. At first had oil change but dint solve. Had to take to Vauxhall (pentagon) for diagnostic. They confirmed timing belt and Vauxhall are doing under warranty but i had too jump through hoops for Vauxhall to confirm they paying for it. I had to prove all services where done properly by providing copies of invoices for services done they looking to make sure correct parts and correct grade of oil was used. apparently timing belt is 6 years or 60k i think they said. So check with Vauxhall. However my car went in 19 Feb was supposed to be a 3 day job but is still in there apparently waiting for part to do with Driveshaft so they say. I did originally get a courtesy car which i was supposed to be paying towards insurance so they said. They have waved all cost for courtesy car now which i still have.
