Dom95

Everything else seems absolutely fine, recently had alternator and battery replaced. Starts happening when the car is warmed up about 10 minutes into first drive of the day, car starts back up without issues. If I select N as it starts juddering itll stop juddering

As the title states, first car and have no experience with cars so my terminology may be off. When IDLE either at a traffic light or stopped in traffic, the RPM counter will go to near 0, the car will judder and cut off unless I accelerate and bring the RPM back above the line between 0 and 1. When it cuts out, radio stays on as if the car is in accessory mode (like a manual car stalling?) Does anyone know what this could be?

Let me start by saying I have absolutely no clue with cars and this is my first. VW Lupo 2000 reg 1.4 40,000 miles on the clock. I have had this issue for about a month now, when slowing down the car starts to shake / judder and will eventually "stall" I'm not sure if this is true stalling but the engine will cut off and the orange battery (Alternator?) light will come on. The radio does not cut out. I have had it checked by 3 garages, I have had the plugs replaced / cleaned, the alternator replaced and the battery replaced but the issue is still happening. Car starts right back up when turning the ignition with the car in P. Pretty sure I've spent £500 getting the above done for no reason and this is either normal for old auto's or an easy fix but any advice would be amazing as I am clueless and lost. The car never cuts out when moving at speed, only when slowing down or reversing very slowly. Also appears to only happen when the engine has been going for about an hour or so.