From your quote:-
A 2nd option is via 'Press Red', select the channel you don't want (BBC One HD or BBC HD) press red, wait for the new BBC selection menu, select the channel you do want, picture is restored, it appears this is a BBC bug, so complain to them. Currently my
Humax Freesat HD box does not show the Olympics Extra button, so I don't know if this will be an issue with other boxes too.
The above works for me - but you have to wait 10 seconds or more for the message to change twice and then I get the channel I want.
It's not appropriate for Freesat - it's a Freeview modification....
Olympics will be over soon - so the issue may go away. Your not going to get better value than the units you have. It may be that Humax boxes will cost less when the new models get popular.