Ride a wave

This is one of our sons in the water today. I saw him at this distance but, no closer! So odd still! He is, among other things, as you see, a great surfer!

Can I ask for some Blip advice please? I want to get more zoom/telephoto but am also considering upgrading my camera body. If any one can offer any advice could you e mail me at claire.brayne@gmail.com ? I would be grateful for any steer that you experienced people can offer me please...