From the way you are speaking, do you perhaps live in the USA?
Things are very different here in the UK.
"Anencephaly - where a baby is without parts of the brain and skull at birth. It is fatal and there is no cure or treatment."
And how is that relevant? Under UK law that is a condition that allows for abortion at any time up until birth. Regardless of whether it is before or after 24 weeks.
"If we lower the number of weeks for abortion. under these circumstances eg we are forcing them to continue with the pregnancy knowing that the baby is not viable and never will be. Cases like this occur and are pure torture for the mothers."
Again, this may happen in the USA but it does not happen in the UK. What you are saying is untrue in the UK.
"The most vulnerable women ... find it difficult to accept/ know they are pregnant or make / get to an ante natal appointment etc etc for diagnosis."
Do you have anything at all to back up your claim? In the UK, 88% of abortions are done by the end of week 9. A further 11% of abortions are done by the end of week 19.
It is only around 1.4% of abortions that occur from week 20 onwards and the majority of these are covered under the ground of there being a serious risk of the child being handicapped and so would not be affected by any time limits anyway.
Can I ask, where you do get your beliefs on the facts of abortion in the UK from?