Thanks Murdockman, yes I will be discussing with the garage on Monday about warranties etc. I don't understand why they seem to want to repeat exactly the same work they charged me for 6 weeks ago. The quote says they did a diagnostic test and i guess this is saying there is a GP problem, but the GPs are new.
I can see from this forum and elsewhere that GP issues with the 1.6TDI Skodas seems to be quite common, but there doesn't seem to be a 2+2=4 solution to the issue. Our Scout was trouble free from 2012 until 2021 and then all of a sudden it got very shuddery in colder weather, which would pass once it warmed up. After the first garage visit the car was great and very smooth, and then after 3 weeks the shudder came back, and it was even worse.
Maybe i should ask the garage to check the valve clearances as well - thanks for the tip.