Sorry may be a bit of a stupid question but where’s the safest point to Jack the rear up on a 70 Satellite ? It’s only to get 1 wheel off, thanks

JF there are no stupid questions, just rude answers & very few of them. You could jack it under the front K in the center which'd raise both front wheels up or at either of the rear subframes for a reat tire & in the front you could hit either subframe also instead of the K. A good plan is to just slightly loosen the lug nuts before you raise it

As Robert mentioned on the front the K member works well, don't forget to use a jack stand while working on it. On lifting the rear of the car the rear end housing works well with a jack stand under the rear sub frame to hold the car up, same on locating the jack stand under the front sub frames

For just one wheel, putting the floorjack pad at the forward spring hanger reinforcement works well. Make sure it doesn't contact the spring itself.
I wouldn't leave it that way for a long time or if there's activity around the car; just for wheel/tire R&R.

Great many thanks for your help

I should have added: level ground, block the diagonally-opposite tire fore & aft, no cheap toy jacks, and I tend to keep my limbs away from the underside of the car unless it's on jackstands...

I’ve always use either one of those reddish grease rags or one of those propoline like pads on my jack pad to protect the finish of the underside components of the car. An iron jack pad against the K member can really abuse a K member.

Always be certain that jack pad is secure to where you place it, to lessen chance that car could slide off it. It happens. Amazon has a number of choices

https://www.amazon.com/Prothane-19-1405-Red-Jack-Pad/dp/B00387A6TC?ref_=fsclp_pl_dp_7

Place jack saddle (floor type jack) under axle center section: if that's the type jack you have. Raise until tires off ground. Springs will compress as you raise. Less total lifting involved. If jacked from a body point: spring(s) relax & need to raise more before tire clears ground.

On my 68 Sat, I have to jack the body up and let the rearend sag to get my wheels off due to big tires and 3 inch long wheel studs.

So you need to have springs sag so tires clear the wheel wells. As noted before: on the frame members in front of the spring hanger is a rigid part of most cars