OK after loads of abortive attempts I am ready to reveal my own simple recipe to the world of Hexus :
500gms Jumbo Oats (dont use porridge oats, they absorb too much liquid and the flapjacks go all hard)
250 gms best high fat content butter (President is the best I found at about 84%
One large jar of Tesco's own brand golden syrup (the 680gms jar)
Plus whatever else you fancy adding, like nuts, dried fruit, or any other "special" ingredients
Right- what to do with it -
Melt the butter in a large heavy pan, then add the syrup. Bring to a rolling type near boil, and let it bubble very gently for about 3 minutes.
Add the oats, and mix well into the butter/syrup.
Line a flat baking tray (mine is about 12" x 10") with foil or parchment and smooth the mixture into the tray.
Bake at gas mk 4 / 180C for about 15 minutes and check - if the outer edges are just turning a darker colour, its done.
Leave to cool and cut into 16 pieces.
These should be slightly moist and sticky if you've done it right