V70: Electrical Door lock motors

[jcparsons]

Hi. I've got a 2008 XC70 and the passenger front door lock is sticking regardless of the keyfob unlock or the driver door unlock button...so I'm having to manually reach over and open it. I've watched the Youtube video that was suggested and he showed the missing spring which is probably what's missing on mine but the XC70 he's working on is an older model to my car.
He continues to dismantle the door lock right down to a motor and mentions that it's made in China.
I have a wonderful local garage here in Solihull who will do the work (I'm assuming it'll take him a couple of hours) but I need to buy the relevant parts first.
Should I buy a replacement return spring which I've found the number for on the Volvo parts site and another engine unit (found that part number too) but really, I'm inexperienced at this stuff and might be getting it all wrong.
What I spend on parts if I just buy an entire new lock - will eventually save on the garage's labour rate faffing around with replacing bits and pieces or what's presently there - so it's going to cost me - whatever! A damage control situation.
Any suggestions...?