OK... here's
Marks Park club on Google Maps. Hopefully a green marker will show, and that marks their parking.
As Stratisfear observed, Judith road runs between Beyers Naude Drive and Barry Hertzog Avenue. Pan the map EAST (right) and you will find Barry Hertzog.
Pan left/west and you will come to Beyers Naude and West Park Cemetery. Melville is south (down) along Beyers Naude. Northcliff corner is north/up along Beyers Naude. The locals have heard all the jokes about "the dead center of town".
As this is Google Maps you can use it to find a route between the club and another address.
The entrance is quite easy to see as you travel along Judith. Turn in, you'll come to a boomed gate. Tell the guys at the gate you are going to TJs and they will direct you.
NB! TJs do not always use the same room - so if you're not sure then
ask the guys at the gate.