Okay, speaking as an MOT tester....
Rear brake pads wearing thin - means just that, that your rear pads are wearing thin. The criteria for failing them is 1.5mm thickness, which is well below the minimum recommended thickness, which is usually around 3mm. Sounds like it will need rear pads and discs imminently.
Rear silencer corroded - they all do, given time. As long as it is secure and not blowing badly, you can ignore this for the time being, just keep an eye on it for security and replace when it gets ropey.
Front discs have a slight wear lip - of course they will, they are designed to wear! They should be checked against the minimum disc thickness criteria (find someone in a garage with Autodata on their garage PC to get the figure for you if you want). As was said above by another member, leave until pads are worn down sufficiently to warrant replacement and do the discs & pads together.
Front pads half worn - as above.
Slight damage to n/s/f wheel inner rim - probably a kerb knock, caused by driving off kerbs. See it all the time, if it wasn't bad enough to warrant a "dangerous" marker on the MOT, and it hasn't affected wheel balance, ignore it.
Front wishbone bushes perished - nothing mentioned for play, ignore it until slight play is detected then replace, probably this time next year!
Rear discs well worn - need attention - As above for rear pads, replace as soon as poss really.
Both rear track control arm bushes worn & have play - replace sooner rather than later, to prevent expensive abnormal tyre wear, which will only cost you more money.
Passenger airbag cover appears insecure - NOT an MOT-testable item, ignore unless you think there is a safety-related fault that you want resolved.
N/s/r park brake effort low - Brake caliper probably needs a clean and lube of the park brake actuating mechanism, best done at same time as rear discs & pads, before it seizes up and costs you a caliper!
Hope this helps.....