Take a look at the state of Eliott Davies' contacts by clicking on the thumbnail.  These are Elliot's words after changing both caps and rotor arms. "My car is now more responsive on the pick up, mine used to hesitate a little i.e.. when in neutral and blipping the throttle there was always a bit of a delay before the revs rose. Tickover also steadier when cold."
 

Herewith instructions on how to replace caps and rotor arms.

Firstly you need to remove the heater blower air guide but loosening the bands at each end and removing the electrical sensor connections.  This is the large black pipe to the left of the picture.

Put a rag in the big black screw-eating hole.

Remove the two screws holding down each cap.
 

We labelled the plus lead just to make sure we didn't screw up. The leads pulled off the cap just using fingers to pull.  Do one cap at a time and replace the rotor.  Just pushes on. The connect up the new cap.  Then onto the other cap.
 

Inspecting Your belt

Now the interesting bit.  Lift off the metal protection plate on the lower master distributor and you will glimpse the belt in two places.  A torch is helpful to see detail. You can rotate the engine by hand or with the starter and inspect the length of the belt.

Click the photo on the left for an enlarged view of the visible piece of belt. (Thanks to Thom Fitzpatrick for this photo)