Sorry to be the one sounding a note of caution but my son had a similar experience, starting reception with very fluent reading (The Lion, The Witch and the Wardrobe) and knowing his tables.
The infant school put him on the gifted register (doesn't mean a lot) and said his work was differentiated by outcome - i.e. he did the same as everyone else but could read and write!
At times I complained and he got more advanced work. He actually did very well as it's a great infant school.
The trouble started when he reached the junior school, on the same site but with a different head. It seemed like I had to 'prove' his ability all over again, even though they knew his reading age and results.
Over the years we also tried to take part in whatever gifted activities might be available in our area - precious little!
Finally this term (year 4) his results nosedived because he was bored and I have become tired of arguing that he needs more of a challenge.
I went to see an independent school and realised the standards are higher and it was where he should have been all along. It's going to cost us a small fortune but we're now moving him. Hey, who needs to pay off their mortgage before they hit 80?
I'm glad I've found somewhere he will enjoy. He tried it for a day this week and said: "Why didn't you send me there before?" Now I feel so guilty.
What's so frustrating is that not everybody can afford to change to the education they need. Expectations in the state sector seem so low. I'm also moving my daughter, who is at pre-school and a more average pupil, after arguing with the pre-school teacher who thinks her age group are too young to start reading or writing! I thought these people were meant to be educators!
So I hope it goes well for you tobytortoise, but keep a careful eye on his progress.