Which wiper blades should I go for with mine fiesta mk6 

Bosch aero 👍

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What size I need 22' and 16'?

Another vote for the Bosch Aerotwins.

Have a look on wiperblades.co.uk and put in your car details and it will come up with the right size. Just find the number of the pack of wipers you want and have a search online, I've found Amazon to be a bit cheaper! 

It's 22" & 16" for the front

The back I couldn't tell you as I just replace the rubber, dewipering soon thanks to KILLALLWIPERS imminent release kit!

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http://www.ebay.co.uk/ulk/itm/351251168637  

these does not look bad 

If they're cheap aero knock offs don't buy them, they'll destroy your windscreen. I made this mistake on my own fiesta :)

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i got cheap silicone ones off ebay work great and last longer than rubber blades 

Till they start putting grooves into the windscreen

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The rear one is 11", I got the Bosch Super Plus Universal on mine

Either go with original Ford ones or Bosch aero.  Like many others, I've tried quite a few different cheaper brands in the hope of finding an equivalent but they're either rubbish to start with or don't lost very long. However what I will say, the last couple of rear Bosch wipers I got didn't last very long so now I use a Valeo on the rear and it's a much better wipe and lasted longer so far.

Had mine off a chap off Ebay and had them for the last few years and 100%, just like the ones i spent stupid money on before.

26'' and 15'' here is the link. http://www.ebay.co.uk/itm/190581059284?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Amazon. Bought two sets at £8 each but I've noticed that in the days since I bought them they've gone up almost £2 a set! 

When replacing my windscreen wipers (including rear), I went with genuine Ford wipers. I found them to be cheaper (only by a few quids) and they're quite durable.

For the fronts I last got some Lucas ones.. Not the best result tbh! Will be going back to Bosch next time.

My spring went in my mk6 rear wiper arm so replaced it with a smooth arm.

http://m.ebay.co.uk/itm/230888581924?_mwBanner=1

Looks much better and clears more screen than the original.

wiper blades are same as a Clio so when I replace the blade I'll be fitting a Bosch.