Well I use this one which I think i got off the forum here a while back, merged with a Delia recipe and modified a bit
20 elderflower heads
2 pints boiling water
900g sugar
75g citric acid
Two lemons
Dissolve the sugar and citric acid in the hot water
Zest and juice the lemon into the water
Slice up the remaining lemony bits and put into the water
Leave the water to cool
Remove flowers from the heads aiming to remove as much green bits as possible
Add elderflowers
Stir in well
Leave for 48hrs with occasional stir
Bottle and freeze.
I use little 250/330ml plastic bottles and fill them almost to the top.
I freeze them upright without the lids on (just in case the liquid expands during the freezing) and then pop the lids on afterwards
Lasts at least a year (because I was just finishing last year's when I made this year's)