MK1 Focus Ghia - various problems... help?

[xsaravtr]

Ok,

So this is the second car and is only used for commuting, but I'd still like it to work properly...

It's a '99 on a V Plate and has covered just over 130k miles.

Things wrong:

• Central locking doesn't work. Checked battery, changed battery, no difference.
• Rear passenger side door doesn't open. Won't unlock.
• Remote boot switch and lock are disconnected because it kept opening on its own, (once on autobahn doing 100mph+).
• Headlamp levelling doesn't work.

Aside from throwing it away, any advice or suggestion to rectify these issues would be gratefully received!!