I have omitted all the heater wiring due to saving mess on the layout, didn't bother with the B+ CT but i've added it now for clarity.
You can't ask for help confirming you layout is right and leave wires out. That's not clarity.
With the B+ fuse, I'm not bothering with a standby switch as its not needed, I thought this is how it should be wired, how would you recommend it?
A B+ stand by switch has nothing to do with a B+ fuse.
Your schematic shows the 500mA B+ fuse in the B+ CT to ground. Your layout shows that B+ fuse in the B+ coming off the tube rectifier. These contradict each other for location.
Regarding the grounding, all the power section is grounded on a tap by the power transformer and the preamp is all grounded at a lug near the inputs, is this not standard grounding?
Yes, I see what your drew, read the Merlin link on grounding before you build that amp.
Biggest problem is you have the B+ CT and 1st filter cap grounded wrong. B+ CT should go directly and only to the 1st filter caps ground lead, NOT to the chassis, then run a wire from that junction to chassis power ground. And run a wire over to the B+ screen filter cap, node B. It's drawn in Merlin's link.
And where your taking the heaters dc stand off voltage from and where you put the 2 x R's and the filter cap and where it's grounded, is not the best place for it to be in the layout. It should not be grounded with the B+ CT. I'd move the dc stand off to the very last B+ filter cap node and inject it into the heater string on the 1st preamp tube.
And I'd move each B+ filter cap to right where it feeds the circuit it powers and form a ground star there. Then daisy chain each ground star B+ node together.
Read the link.