[DTV]

While slightly unusual, any policy change would presumably have to be legislated for via the said parliament, so it is really not possible to have "policy away from the scrutiny of parliament".

Not to get too into the constitutional weeds of it, but not really the case on either these days. Ministers have a accrued a lot of secondary legislative powers, particularly in the last few years, so there's a fair bit of policy that can be changed without parliamentary approval. Also, in terms of scrutiny, the British parliament is so relatively weak that legislative scrutiny is fairly minimal and non-substantive.

In terms of statements to Parliament, the expectation is that Parliament is informed of policy first. However, whether Sunak has breached the rule as outlined in Section Nine of the Ministerial Code depends on how you interpret "when Parliament is in session". Some might argue that the Commons being in recess (as it currently is) means that Parliament is not in session, however, from a technical perspective, a parliamentary session begins with the State Opening of Parliament and ends when it is prorogued - Parliament is currently in session, the Commons is just not sitting (though the Lords is).