Right First off if you have a 1.2 or 1.4 you "should" be able to do this from above with a bit of care.. if you have a 1.9 have "fun"
The Bulb in question is a H1 55 Watt
on the 1.2 you can fit a small family in the void however having seen the 1.9 you might be able to fit a hamster........
if you have a 1.9 your best bet would be to jack and axle stand the car and remove the wheel and arch liner (unless "T" has stolen your under tray)
this (the arch liner) is held in be several screw and plastic "nuts"
right assuming you have now managed to get to the back of the lamp
you need to remove the cover (Lee Punto says he needed a rubber strap wrench to open his however i have never had a problem)
this removes with a small turn Anti clockwise.. (about 1/8th of a turn)
at this point dont pull the cover too hard as it is still connected by wire to the bulb you are about to replace and you don't really want to damage the connector
The Bulb in question is a H1 55 Watt
on the 1.2 you can fit a small family in the void however having seen the 1.9 you might be able to fit a hamster........
if you have a 1.9 your best bet would be to jack and axle stand the car and remove the wheel and arch liner (unless "T" has stolen your under tray)
this (the arch liner) is held in be several screw and plastic "nuts"
right assuming you have now managed to get to the back of the lamp
you need to remove the cover (Lee Punto says he needed a rubber strap wrench to open his however i have never had a problem)
this removes with a small turn Anti clockwise.. (about 1/8th of a turn)
at this point dont pull the cover too hard as it is still connected by wire to the bulb you are about to replace and you don't really want to damage the connector
Removing the wires once the cap is off
Right you are now left with this:
so you need to remove the cream plug (this has 2 cables to it one for the live (+) and one for earth (or neutral (-) )
It just pulls off so long as you pull it Squarely away to the back of the car)
Now to free the bulb itself
this is retained by a double spring loaded clip which is biased to be always spring closed and clamping the bulb in place (unlike the Headlamp bulb which is "hooked shut")
From this you need to open one wire up at a time using finger pressure ease the wire back until you feel resistance there are 2 plastic posts cast in the back of the lamp to retain the spring clip (one on each side of the bulb) to enable you to get the bulb out (i have coloured one in on paint to highlight it)
do one at a time
then you end up with this
Replace the bulb
Now take the bulb out and get your new one ready
replace the bulb so it sits flush the 2 dimples on the collar of the bulb sit in the 2 holes in the back of the reflector ( you can see one of the holes high lighted below
Ensure you do not touch the glass envelope of the bulb if you do it will need cleaning with a pure solvent such as Methylated spirit or Isopropol (spl) alcohol or the oil from you skin will cause the bulb to fail