VFR Does not require that you be in sight of the surface, that is just a restriction on the UK issued PPL. With the IMC rating or IR, this restriction is removed and you can fly VFR on top.
When you enter cloud in class G just inform ATC you are IMC (and IFR) and comply with IFR. Cruise at quadrantals, climb and descend as required, there is no requirement to be straight and level before becoming IMC.