cool, so if i under stand right,
option 1: teminate the neutral by not connecting up.
No - if you just terminate it, then the lights won't work, will they. Option 1 is don't cut the neutral where the cable passes through the switch on its way to the first light.
so what is the ideal/safest way bearing in mind its outside.
It all takes place inside the switch enclosure, so any method will be as safe, or as flaky, as any other...
Dont know fuse size at home, but the electics i am connection to were all done professionally
Yes but is the socket on a radial circuit, or is it a spur off a ring?
Did you decide to use a switch rather than an FCU because you know that's OK, or because you don't know how to do it properly?
Do the manufacturers of the lights specify a maximum fuse/MCB rating?
I have heard of P part
Is it your intention to comply with it?
1) the lights are mounted to boarding on the treles and the wire is drilled through the back, through a gromet and into the light.
I can see how a grommet might be OK for round cable, but I doubt it would maintain the right IP rating with 1 or 2 T/E cables. Ditto where it goes in and out of the socket & switch enclosures - do the instructions for those allow for the use of grommets, or do they specify glands?
2) I usesd t/e as the lights needed an earth & i had the cable spare in the shed.
Do the makers suggest the use of T/E?
Is it the right size of cable given the MCB that it's on?
Will it be adequately protected against mechanical damage?
Will it be adequately protected against UV damage?
Will it be concealed at any point?
3) the socket is on its one circuit connected to an RCD unit in the shed.
See above - it it a radial or a spur?
these lights will only ever be used in the summer/dry.
Yes but they, the wiring and the switch will be outside 365x24, won't they...