right my car failed its MOT last week because of the boot lid! it wont stay shut,the only way to keep it shut is to get in the car and put my C/L

ghead on and it stays shut,no i have sprayed the latch with wd40 feels a little better.
I was wondering has anybody had this problem or how can i solve it?.and is it easy to fit a new boot lock if this one has died!!
many thanks folks,this is my first post of many!!
cheers
ste