I note there is a significant difference between men and women.
it’s a survey of about 1000 people roughly evenly split between men and women.
traditionally it is men who are expected to join the army.
obviously these days both men and women are in the army but in any future war it’s unlikely men and women will be conscripted equally purely because pregnant women and women with children under the age of 1 are not going to be useful in the army.
also purely on a logistics ground if you conscript men who have children and women who have children no-one is left to look after the children and they will all have to go into foster care (with whom?)
usually countries conscript single men first, often with exemptions for nationally important industries (eg farming and coal mining in the Second World War) then men with children. If applied equally then it would be single men and single women then onto men/women with children.
single women in the Second World War largely joined organisations like the land army so they replaced men on the farms etc.
historically Britain has had many fewer invasions than other European countries because of the sea between us and the continent. Russia is a problem but the likelihood they will physically invade Britain is very low.