Have I left this too late

If I phone up I can only buy a maximum of 50,000 points in one go, if I do this are the points available to be used straight away??

If I purchase 70,000 points online tonight before the 8th March deadline, will I be able to convert them to Tesco Clubcard Points later, as I doubt I will have access to them until the 9th without activating the new 10% rule.

Why didn't I buy these months ago