Just a word about the level capping that is becoming prevalent within London airspace.
Please, if you are capped, try not to moan at the controller. The level capping is done to keep the New en-Route Centre (Swanwick) sectors that have to be "band-boxed" at a manageable level. Usually, if the controllers on those sectors are able to offer higher, they will.
None of us "downstairs" like to keep aircraft artificially low (it clogs up the lower levels for a start !), and we fully realise the penalties involved in doing so.
If you DO wish to complain, please level it at NATS Management
who went ahead with the opening of the New en-Route centre (Swanwick) knowing that they did not have to staff to man it properly.
This situation is likely to last for quite some time.
