boot lock

Hi

I have a mk1  2.0l elegence and the boot lock mechanism has packed in, a small star washer fell of about a year ago, popped it back on and all okay. Recently the boot wouldnt lock so off with the panel, and i think another part and the star washer have fell off .I have fine toothed the boot and hatch and cant find a thing.I have attatched a picture and the part nos appears to be 1u6827565 something

 I can lock and unlock boot by clambering in the back,which for the amount of times we use the boot is not a great hastle,but its annoying.and would rather have it locking/ unlocking externally,To be honest had the car for a few years and we have always had to open and shut doors/boot by key the remote buttons never done a thing even when replacing batteries. Just now the key will lock and unlock the doors when the boot is either locked or opent I have tried to look at schematics source new locks etc. It now looks like i am going down the re claimed srcap vehicle route,

 My big question  i assume i have to buy the unit with a key that works the lock,as there are ones on sale with lock and no key,if i buy a second hand with key the opening/closing of the boot will still open and lock doors of the car as does the original,and wont effect having to use the original coded keys in the ignition so now instead of the original key i will have a second key for the bootlock or can the bootlock barrel be changed to suit my coded keys,

 I was even looking at some of the less expensive second hand ones thinking i could just make one out of the two and keep same locks original keys

any advice

many thanks John

Edited 6 March, 201610 yr by munro