Cylinder Head Gasket Replacement? ?

[Nick Turley]

1937 Ruby Saloon ARR: 
Following a radiator refurb & replacement of  side branch studs / gasket I added antifreeze & checked for leaks.
All appeared to be in order. However after a few days I found the sump was filling up. The antifreeze had presumeably found a low spot between the cylinder head / block / gasket where before no such problem had been experienced. 
I am yet to remove the head. 
As there was no leak prior to the introduction of the antifreeze will I get away with just replacing the gasket? 
When replacing the gasket is a jointing compound required? I have been advised that greasing the gasket is an option which helps with future separation of the gasket from the head /block . 
Some advice on the above would be greatly appreciated.

I used to grease head gaskets lightly and fit and only very occasionally experienced a leak.
Now I use Copper silicone (halfords) sparingly on the good advice of Steve Jones, I then leave 24 hrs before filling with coolant.
 Since the change of procedure never had a leak on any car head gasket (done quite a lot).
Torquing down is important 20ft lb cold and a re-torque after the first run.
Your torque wrench needs to be good at that sort of range ( I use a small Snap On).
I have come to the conclusion that the  "modern" seven gasket's middle sandwich is harder than originally,
so they might be a little less forgiving. 
I might be talking rubbish here !