Recently bought my 6 year old daughter,a Carrera Luna 20" bike off ebay for £50.Its about a year or so old and has one or 2 scratches but rides really well.Very similar spec to the Boys Blast.
Recently bought an as new Claud Butler 20" trade in for my gfs 6 year old,for £40 and thats great too.
I wouldn`t worry about getting a big name brand for a kid tbh.In a year or 2 you will be trading up to a 24" bike anyway.They tend to trash bikes too,so just make sure you get a light aluminium frame and decent components.I reckon the kids Carreras are every bit as good as the Spesh Hotrock.
