Wooden worktop and upstand. So many questions....

[Claydon Lad]

There's probably some regs out there that will tell you so many millimetres that the gas hob needs to be from the upstands.
But as you mention 616mm width tops, you've already got 16mm more than a usual 600mm one. 15mm thick upstands? You'll have enough space to play with fitting the hob. 

If you start the hob cut out 50 - 55mm from the front, you'll be fine with that.

You'll have to post some piccys afterwards though..... That's for swearing on the forum ...feckin "Howdens",