RE: Pre-decision scrutiny
I personally disagree with the advice where it states that it is inappropriate to consider an issue as it is being formulated, before a decision is made. This can often be a valuable exercise since (as you would expect) scrutiny can make suggestions that lead to improvements in the decision.
The longer in advance scrutiny is able to input into decisions this way, the more useful it will be in terms of value added. For major business issues anywhere between six and nine months prior to an expected Cabinet decision is usually a good time to try to get involved. This kind of approach minimises the risk of call-in, which as many recognise can be a blunt tool (albeit a useful one in extremis).
As an aside, use of the Forward Plan for this purpose can often be of minimal value - I can't speak for yours, but I have a low opinion of Forward Plans generally as items tend to appear on, and disappear from, them arbitrarily. Your council probably operates using programme management principles whereby major projects, strategies and plans are developed and delivered further to a corporate programme - this document, which will be used for management purposes by CMT - is probably a more accurate and valuable source of information for scrutiny as it will provide more detailed information on where in the process scrutiny can and should get involved in the process in a way where it can make a positive and constructive contribution.
As a large caveat to all of this, I should stress that while I can happily talk about general principles, scrutiny can and should work differently in different authorities, and there may well be a compelling organisational reason which isn't cited in the report why it is thought inappropriate for scrutiny to be formally involved in policy development in this way - for example, there may be other methods for non-executive members to feed in.
Research and Information Manager, CfPS