at least you can get them now.
back when i was playing with this old stuff, it was off to the wreckers for a whole lock mech.. with ford parts saying NLA (no longer available) for anything you ever wanted.  (plus side back then, you could buy a whole car for $500 or less and get 3 or 4 of those springs and a host of other spare parts)

Thought this was the case..After checking passenger side mechanism i discovered me spring gauge was too thick and impossible to get it to fit. squashed the spring in vice grips and forced it in and now it works. My Dickheadness for getting the wrong spring.  

there's a hole either side in a gap,  it just needs to have one of the spring parts in each side.. bit of a fiddle to get it in there. 

found a photo of it on ebay. edited it to show where it goes.   

Cant see which way the spring gets installed in that video ! Have tried to install and no luck.

Forgot i had this  tonneau cover that was given to me too pay for helping out a recovering and delivering a crashed motorbike some 3 - 4 year's ago , don't fit my ute. Any one need it ?

grease the pin, it latches on, grease that spring latch part, oil the door hinges and oil/grease any of the mech parts..
if you probably drowned that key lock in some WD40 or similar it might flush the dust out of it.. ideally locks are supposed to have a graphite powder in them, but they can still get that oxidized build up that WD40 etc seems to prevent.. (for a rarely used lock, i'd go with the WD40..)

you can pull the tumblers out of that lock easy which will also make it easier to turn. ..any key/screw driver will open it.. but it's not likely going to have people trying to get in there.... same process for the door locks if you wanted.. My Dad had one lock on his car without tumblers for decades and a spare ign key under the seat for when he went fishing.. just incase he lost his keys overboard etc. (these days they smash windows etc rather than play with locks anyway)

Just had enough DW 40 left in my Nozzle can to fill it up, After a few jiggle's and cuss word's it turn. it feels rough to turn so will go buy some more WD 40 before i open it too give it a service. thank's  deankxf

yeah they are pretty bad and very hard to line up to work properly.

i've had several that had home made latches and gate locks etc and one had the pin filed down so it would close easier (this is the one that fell open easily)  i used the number plate screws to screw into the panel behind . (did this by accident once also)    good luck, if you can turn the key, it should come open with some prying   

Thx for quick reply. Ignition/door key fit's the wheel lock...will give it a spray with WD 40 and give it a go . Was told i would need a crow bar to open it as i remember at Vehicle hand over. At least now i know i have the right key in lock while attempting to unlock it.

i never trusted those latches on them, they often either stuck or didn't latch in my experience (perhaps because they'd backed into a trailer hitch etc too many times from previous owners   they should match one of the keys (i think it's the door/ign key) *the one that fits in the hole... glovebox usually matched the sedan boot key. last ute i had, i pulled the tumblers out of the lock so a screwdriver would open it or any key that fit due to it being full of dust/dirt etc.    if you suspect you have original door/ign locks, i'd firstly spray it with WD40 etc in the lock hole, in the gaps to the lock and try wiggling the key as you try turn it while putting upward pressure on the door.    if you can figure out where this is in relation to the pin it latches to, you can drill a hole or poke and prod to release it.    they can be really hard to open even when everything worked.. and hard to close (i screwed mine shut in the past due to them coming open on dirt roads)