Judders when accelerating and a little amber engine/gearbox appears intermittently after about 15 minutes

Hello , I'm Danny.

Sounds like you definitely have a misfire. The first thing that needs to be done is have the check engine light code retrieved.Having the light come on means a code or codes are stored in the vehicles computer. If you don't have access to a code reader/scanner most auto parts stores have a tool loaner program and can rent you one.Some parts store like AutoZone can check the codes for free.Here is a tutorial that shows what is involved for code checking:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

After this is performed get back to me with the code number(s) and we can properly diagnose the problem.Hope this helps and thanks again for using 2CarPros.

Danny-