i Have a Mk1 punto and the reverse lights went, bulb & fuse both good.
The fault i had was with the lighting unit itself. IF you takes these off (Mk1) - two bolt holding each one on
(Mk1) - Single eletrical plug
(Mk1) - inside held in place with 2 mabey 3 cross head screws
then move the bulbs slightly, reconect the plug without the outer casing and try, with ingition on but without engine running, putting the car into reverse, if they still dont light up, leave the car's ingotion on and try moving the bulbs around again, if they light up:
force the Metal back plate where the bulbs rest into the postion where the bulbs light up, i used a pair on plyers for this with the bulbs still lit so you know if you lose the connection.
If they still dont light up, clean the metal parts with vinigar (How ever you spell it, the stuff people often put on chips - not salt!)
dry them, refit and repeat the above to aline the bulbs.
If after doing this the buld still won't light up then do about replaceing the reverse switch
When i took my lights off i found that water had gotten inside and partly corroded the metal work in the lights, the vinigar got rid of this