I too had a bad experience with GKR. Two of their "instructors" came knocking at our door (be very wary of karate instructors going door to door!). They told me that they start children aged from 5, I told them my DS was only 4 so he looked at him and said "erm, that's ok...we'll take him" (I later found out that they're not insured for children under the age of 5).
After a lot of pursuation I agreed to have him come back and show me some info, this is where I found out their extortionate prices. Apparantly their join up fee was £80 but they were "doing a special offer" and we could join for £25, I later found out that this is their standard selling line! I wasn't at all happy about having to pay to join a club which we had not yet seen (be very wary clubs like this) but I stupidly paid the fee and agreed he could join. I then found out their lessons were £5 an hour!! this is also extortionate, most karate classes charge between £2-£3 for upto 2 hours.
Anyway we went to the class and were not at all impressed, the highest ranking student was an orange belt and their "instructor" was a cocky 20 something bloke who's main interest was making the parents laugh than actually teaching the students anything. The vast majority of the class were doing all the moves wrong and they were not corrected, just ignored and for £5 a lesson you expect a little more.
On his 3rd lesson I got talking to one of the "instructors", during the conversation he said "oh yeah, I've been doing it for a few months now, I'm getting really into it!"....a few months and he was wearing a black belt?? it should take anything from 3-5 years to get a black belt!! and this man was also teaching?? I later found out that at GKR you don't "need" to be a black belt to teach...infact anything from a yellow belt upwards can teach, they just do a little course and then stick on a black belt. This IMO is wrong.
After about 5 humerous classes I took my son out (far too many examples of bad things to list here in those 5 classes) but when I looked further into GKR I found some pretty disturbing stuff about them.
I know a black belt (a proper black belt! in wado ryu) who was so concerned when he started getting all these ex GKR students at his class that he posed as a white belt and joined a gkr class, he stayed for 10 minutes before walking out in disgust.
I have an orange belt in GKR and I honestly think that if I stuck a brown belt on and joined up at a GKR class they wouldn't know the difference.
Also, how can GKR students take part in sparring competitions when they're the only style of karate that is completely non contact? surely they wouldnt last very long sparring against a proper karate student who is used to contact sparring?
Personally I would take your son to either Taekwondo, proper karate or Kung Fu. Please avoid GKR like the plague.
Please avoid them at all costs.
(p.s. a few months ago another gkr "instructor" came to my door and tried to pursuade me to take my kids OUT of their current taekwondo classes and join their club! as if I would really throw a years training and 2 grades away just like that! a real karate instructor would never suggest such a thing).