Thanks.
What I am specifically looking for is what it says in the 737 (variant) performance manual.
In the old CAP698 it used to say "If adjusted V1 is less than V1(MCG), set V1 = V1(MCG).
In the new CAP it states "If adjusted V1 is less than VMCG take off is not permitted"
I think the latter statement is incorrect so any quotes from performance manuals will be much appreciated.