Jacking points

Well having solved the  wheel nut problems the next thorny question is how to raise the car? A search of the excel.net shows that this is a perennial problem - largely because its hard to believe that GRP is so strong that you can jack on it. Well I know that you can as I did so on my Elite but even so I'm not greatly happy about supporting the car for maybe a couple of weeks in this way as the chassis and engine/transmission are effectively just hanging from the body by their bobbins! ...And as anyone who has ever been suspended from their bobbins can tell you it can certainly make your eyes water!

As I can gather from the forum the threads suggest
1. Jacking point metal plates will rot away leaving the jacking points unprotected. Dont use the scissor jack IF this applies (probably OK if jacking points still sound).
2. Don't jack under the jacking points with anything else unless you have packing- piece of wood to spread the load.
3. Jacking is best done under the front cross member to raise both wheels at once but access for a trolley jack is difficult unless you can drive onto some blocks or a ramp first.
4. Jacking at the rear can be under the diff (not really recommended unless for very brief lift and onto stands) and it could do damage. The suggestion is to use the lower diff frame mount although I'm not sure where that is!
5. When jacked up, get the  car onto axle stands placed either at a) the jacking points with padding b) under hubs/suspn arms with padding c) a wooden cross beam going across the car and taking the weight ....?

However despite this wealth of advice there isn't a single diagram, for instance where should this cross beam go? Can you still jack under the jacking points using wooden packing if the jacking points themselves have vanished? If the GRP is damaged at this point does it matter in terms of structural solidity of the car? Without diagrams or pictures its really difficult to know where to jack/support if not at the jacking points- and as I found out, for me this is potentially a problem.

My rear offside tyre has the worst leak- so first thing was to check out my jacking point for that wheel- no plate and a nasty shock!

Rear Offside jacking point- no plate and a nasty hole!

This is very worrying with a hole- circular mark which can be traced right around the jack point suggests a previous jacking attempt with an unprotected trolley jack (cup support) at this position. Clearly the box section  has been stressed away from the strong point and cracked- but is this a serious problem and can it be repaired?

Rear Nearside jacking point- missing the plate but at least its not holed.

Time to look at the front points:

Front offside

And the final...

Front nearside, plate still present

Front nearside seems the best preserved with jacking plate still present but covered in GRP goo

Its not immediately clear to me whether these points are usable (even with timber packing pieces!) and I certainly don't want to crack the body. I think all bar the rear offside should be OK so perhaps some tentative jacking is needed to test this.  My biggest worry remains the rear offside- which is of course the one I need to get to first! 

Its not clear how jacking points should have been attached but perhaps they were just stuck on with GRP- all odf the sites are surrounded by what looks like isopon but was this a factory installation or a later replacement? Another mystery is that all of these jacking points have a central circular indentation that and most seem to have a red cup-like feature inside this. I had though that this is part of the reinforcement plate- but a look at the new plates on SJSportscars shows that in fact these simply have a hole that would locate directly over this red feature. So what is it exactly and is it load bearing?