Siting of main stopcock

[JohnW2]

@denso13 - I've just realised that you didn't respond to my question (about having rodding access above the highest branch of a stack) when I wrote:

..... As you say, it obviously wouldn't do any harm, but is there any point, if it's not normally done? Is the implication that a blockage in a vertical run of soil pipe is very rare?

Since I don't recall ever having seen it done, do I take it that blockages in vertical, or near-vertical, runs of soil pipes is very rare?

Talking of 'vertical', do I take it that (within reason) the 'vent' part of a stack above the highest branch does not necessarily have to be particularly 'straight and vertical'?

Kind Regards, John