Replace U&O garage door spring - DIY or not?

I have a 20y old Garador up and over canopy garage door where the spring in the spring pack unit (PN57/1) has snapped.

Is this an easy DIY fix or does it require specialised knowledge or kit (e.g. spring compressors?). Would it be a case of replacing just the spring or would you replace the whole unit .

Any thoughts advice is welcomed.

John

if you are a handy guy and strong then sure it can be done in a couple hrs. remember to get a friend to help ,you should always have someone there to call the ambulance and i dont mean your wife, hmm... on second thought some women are very handy , but she might just end up saying i told you so! but if want to give it a go i can help, just message me back and i will explain it to you this weekend. ok