Advice please!

When in middle ring and either of the bottom gears at the back (the big rings on the cassette – I can never remember if that is top or bottom…) the chain skips from middle to granny ring.

Is this a front derailleur issue? Any thoughts? FWIW chain and cassette are newish, and middle ring fairly so.

yep, thats most likely front derailleur, probably could do with a bit more tension on the cable, which you can use the barrel adjuster on the shifter (turn it anti-clockwise 1/4 turn, try again then repeat) HTH

ah, ok. I put new inner & outer cables on lot long ago, so it’s probably stretched a bit

anti clockwise as you’re sitting on bike or facing it?

looking at the shifter along the cable.

http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50rparsys-0018-downloadFile.html/12)%20Front%20Derailleur%20Installation.pdf