londonmama -- I think you're not going to have a lot of luck keeping that nap at 1 for the next month. His A time is going to grow, and he's just going to need that nap to be later in order for it to be a decent length. Right now you're keeping it at 1 at the expense of nights, which is causing you the EWs. Those EWs will then REALLY screw up your days b/c he'll have a hard time making it to 9:30 for lousy 30 min nap! So, you might just have to let him do his own 2-1 thing, and then just hope nursery will take things as they are when he gets there.
In other words, I'd probably give him that 30 min at 9:30 and then I'd give him nap #2 at 1:30 at the earliest. Then, if nap 2 is still short, I'd move the 9:30 nap a little later to shorten the A time between naps.
henry1: yes, move AM nap later and keep it short. PM nap will probably be fine where it is, but you may have to move it a bit later as well.