At the signature restuarants (Artists Point, Jiko, Citrico's, Yachtsmans Steakhouse, Narcooses) they request business casual. They specify no t-shirts, tank tops, cut-offs, etc. Collared shirts and dressy shorts will be fine.
V&A's requires a jacket for men (not a request, a we will not seat you otherwise). Bistro requests collared shirts on men, jacket preferred, suitable dinner attire for women.
Anne