Update - I found some bike degreaser/lubricant spray thing and chain oil in shed, sprayed degreaser on cassettes and chain, then oiled the chain. The bike changes gears much better and goes much smoother, doesn't make weird noises any more.
>>2038387>>2038388Rear derailleur changes gears ok but the front derailleur is weird. Going from big cassette to small cassette is smooth but when I try to change from small to bigger cassette I have to hold down the button until it fully catches on the next cassette while it's making a horrible grinding noise, if I just press it, makes noise grinding against the derailleur and doesn't change gear. I take it that the front derailleur needs adjusting? Or could this be worn cassettes?
>>2038401Didn't know evaporust existed. I'll definitely do this for a more permanent solution.