V8 Engine health question

I have been assessing my V8 Discovery before starting to refurbish it fully. I've weighed up all the rusty bits, which if I'm honest there weren't many - 2 tiny patches right at the bottom of the rear wheel arches, slight surface rust on the chassis, driver inner door has a hole, that's it really. I've already done the suspension, steering & swivel joints last year just after getting it so they're all in order.

Then I had a quick shufty at the engine, it sounds well, no smoke, uses no water but has a camshaft tap on cold start up, leaks oil from various orifices (what Landy doesn't). I've done a compression test and the results are as follows

Cyl 1 - 162 2 - 169
3 - 173 4 - 172
5 - 173 6 - 170
7 - 165 8 - 170

I'd like opinions on the results please, are they good / bad for a '97 plate with 76,000 on the clock???

In the near future I'm gonna do the camshaft and address the oil leaks but was wondering is there any need to do the heads whilst there??

If your gonna do the cam shaft then your gonna pull the heads any way, what sort of tap ??? Are you sure its cam shaft and not rockers ??
Here's a picture of one of my rockers

When you start it from cold, there's a tap tap tapping, coming from the middle top of the engine, which seems to disappear once the engine gets up to normal running temperature.

Correct me if I'm wrong but I thought the cam & followers could be removed without removing the heads?