Is it just for playing music through to the Kids? Im sure you could pick up something cheaper than £200. Let me know what it needs to be used for if you havent already bought something.
The UCube is 80w RMS with a max 400w. Its got a built in MP3 Player you can plug a USB Stick or SD memory card into it and use the play and stop buttons on the machine. Its also got Line in and outputs or Jack / XLR which you can use to play your MP3/Ipod through it. Its got a rechargeable battery 3-5 hours if you dont have a plug at times.
The thing i quite liked with it is the small mixer on it with the levels etc and you can mount on a stand at times when needed - £159.80 Delivered.
400 Watts RMS or 800 Max which would power you through any School type hall and be perfect for outside for parties / fun days or at events where you need a mic to get people over to your stand. Its all on wheels too, again with the onboard mixer and 2 mic/jack inputs for a mic or ipod / music player. This ones also got an option to link up to a 2nd speaker or amplifier if needed to plug into a larger system. - £184.80 Delivered.
Ive never used either system hands on as its mostly band related with larger systems of 800W + i use but im looking at smaller systems and have seen the Skytec one used many times for Street Performers, Nurserys etc. Skytec are always easy and i can get parts for them in a day or two so you know if the speaker went dud or blew you can get an easy replacement.
Hope those suggestions are helpful! PM or reply if you got any questions or have another system you had looked at.