Advice please

Family holiday in Pembrokeshire last 2 weeks of July - nearest water I can see is Western Cleddau and Llyn y Fran.

As a modest Yorkshire river angler I have zero experience of

1) Sea Trout
2) Reservoir fishing
3) Salt water

So what should I do with a sneaky few hours?

I'd go for the Llys y Fran reservoir trout are trout anywhere.

BK