Well a change of fuel filter seems to have made a huge difference in economy and a little bit in noise.

 

Don't think about skipping it at service time and personally I think i’ll be doing the next one at 40k ish miles.

 

If you’re self servicing it’s a 5 minute job and well worth doing with a high quality filter.

 

Mann seem to have the wrong part listed as when I got it from ecp it was much shorter than the own, ufi and Bosch ones.

diesel engine ?

the old 1.9 tdi engine had 2 different sizes of filters, I was given the wrong one as well and didn't realise until I had removed the old one  

ended up taking the old filter with me to make sure it didn't happen again.

 

any problems with air after changing ?   ie rough idle, engine cutting out etc

I usually fill the fuel filter canister with diesel before swopping to prevent any airlocks .