I just double checked the limits and i was mistaken, I had previously looked them up so not sure where i got that from.
Irrespective of that, i never really fly high as a rule anyway and think i was probably close to 400ft in here but cant say for sure i broke the rule on this occasion.
I will bear 500m line of sight and 122m high in mind on all my future filming.
Thanks for correcting me on this as i always try to fly safe and within the law.