Sure looks like there's no queen in there, you should get one. To make sure put in some young larvae if they build queen cells then you probably do need a queen.
This is getting a bit weird.
I checked them out again this morning; they've moved down onto the capped brood I put in, quite a number of which has hatched, so the numbers in there have increased noticeably but still not overwhelming; they're pretty well all clustered on the brood and stayed put on those two frames whilst I took them out and examined them, also every single vacant cell had a single egg in it (ie no multiples at all), however, even after going through the hive, which is still very small, only two deep frames fully drawn, 2 others partially drawn but already filled with sugar syrup, filled, I still COULDN'T FIND THE QUEEN! And that was with 20 minutes stood staring at basically 2 frames. Had a look at others too but no action there.
I didn't see anything older at all though, so could I have a laying worker (but wouldn't I expect to see multiple eggs in cells) or does the queen's abdomen stay a similar length to a normal worker until some time after she's started laying?
My thinking now is to await developments - I'll leave them for say 12 -14 days to see how they look, if ALL of the cells are all enlarged, I'll assume they're drones and therefore a laying worker and take steps to requeen? If they stay worker sized, then I've got a queen (somewhere). The eggs are stood upright at present, so I'm assuming they've only been laid in the last couple of days.
Oh and no queen cells were made but I'm not sure how much suitable brood I had on the frames I dropped in there, so there's a question-mark over that anyway.