Hi all, my car failed mot due to above problem and mechanic said he will charged £110 for the replace spring. I searched on the web and most people mentione its better to chabge both side at the same time. any advice will be much appreciated. which generic brand is good.

yes, both should be changed and sachs is a decent brand, well one my dad uses and euro car parts supply!

http://www.eurocarparts.com/ecp/c/Ford_Focus_1.8_2007/p/car-parts/suspension-and-steering/suspension/coil-spring/?627591480&1&ddca16f7e9e68e498cf8fe4b7fb17c05c81faaf9&000073

If you're doing the spring you're as well changing the strut mount bearing as well or you may find that once the springs done the bearings shot and it all needs stripped again its also a good idea to do the drop link

Euro car parts you'll get two drop links for £14

Strut top mount bearing was about £25 each

May sound a lot but its just easier while its stripped since he has to remove the drop link and the strut bearing it wont cost any extra to replace them with new ones