Sleep trickiness

Ari has clocked up a few days of no daytime sleep. As any parent of a toddler will understand, this is a frightening prospect.
After days of trying to attribute it to The Heat (we've had a shocking run of near 40C days recently), I came to the conclusion today that he may be dropping his daytime sleep.
I may be overreacting (as is my usual style). But Rob and I suddenly have to face the prospect that our blessed 1-3 hour toddler-free time could be coming to an abrupt end.
But, as I remind myself constantly, we have lived a charmed life compared to some other families with little 'uns.
Ari has almost always slept through the night. For some parents of 2 year olds, this is a situation they could only dream of.
We'll see what the next few weeks brings...