Ok so here's the latest update. Day 12 for the majority of these little guys.
They have been happily feeding on algae wafer powder, haven't been anywhere near any veggies, just not interested. At this age I'm not prepared to take away the powder to see if they move to veg. They are about 10mm and look pretty cool. The fry saver is working a treat to ensure that they are in effect 'sitting' in food at all times - no need to go looking for it. I syphon out and re-feed twice a day to keep everything clean and tidy. Growth rate seems pretty good, still have 11 out of 11, they've come on a lot since the last photo.
In case anyone wants to know I use a craft knife (take care kids!) to shave a fine powder off Hikari Algae Wafers and Tetramin tablets, mix this with tankwater in a syringe and use this to add a fine layer of the mix to the fry saver. It's important to clean the old food out regularly.
The female who I suspect laid these is fattening up again and getting feisty so I may need to make another fry saver.