Thanks to everyone for your input, thoughts and suggestions. Plenty for me to go at.
The consensus appears to be Losi Mini 8ight, Tamiya Mad Bull, Maverick range, and LC Racing.
I will do some research and have a look.
Boys will also get to look at MS website over the coming weeks/months - I'll just happen to be browsing and let them have a look.
Ultimately as they are twins, they both need to have fundamentally the same car, so if one has a Firestorm the other can't have a Mini 8ight! Just won't work like that, hence either 2x the same or something like these Mavericks: all virtually the same, http://www.modelsport.co.uk/maverick-rc-electric-models/rc-car-manufacturers/1163/9900/990010&MSAttributeID[82]=9
(Am actually quite tempted in getting myself a Losi Mini 8ight !!!)