Can anyone give me a pointers on the above job before i set about it?
Does the front bumper need to come off?
Thanks

I take the front bumper off. Put some garage mats on the floor to protect the paint. The first time can be a struggle due to rusted bolts but they really should be taken out before they seize solid.
Grill panel has four small screws
Three M6 bolts at bumper top under grill panel
Two M6 bolts under front middle of bumper
Two M6 bolts under each front wing. These need a long extension and ratchet handle.

Mine are now all M6 stainless socket heads with thick 20mm washers and anti seize paste all the way up the threads. Stainless accelerates steel corrosion so needs the anti seize.
Leave two screws in the bumper top. Remove all the others and do the easy two last of all.

inner wheel arch for one of the bolts. I just undo half and force my arm in.

For the life of me I can't remember why but needed a different spanner or long reach spanner something that other than my standard 3/8 socket set here.

pretty sure I didn't undo many bumper bolts just enough so I could push it down a bit to push the lamp forward

To be fair I did the 100P headlight before I did a 1.2 headlight. The 100HP has a brittle front bumper that just doesn't "give" so I had to take it off the car. A couple of weeks later, a deer took out the whole front bumper and the headlight I'd just fixed.

I was glad to have done it because three of the four under wing bolts were very rusty. The panels were fine and some copper grease sorted out the replacement bolts. You do need 20mm heavy spec washers. The easily available 25mm "repair washers" are too large and too thin.

The 1.2 it was not difficult and I was able to properly protect the bolt threads.