Many airlines allow commuting as long as you are responsible and don't let it affect your employment.
So how is taking an action that you know will lose your ability to commute from your chosen domicile in South Africa acting responsibly?
It seems that you also misunderstand what Legal Industrial Action means. It does not mean that the company cannot take any action against you. It does not mean you cannot be sacked - you are in breach of contract and can be dismissed for this. What it does mean is that if you are sacked within a twelve week protected period then that dismissal will automatically be deemed illegal and you will be able to claim some limited compensation.
Your call to ballot now without allowing your colleagues to have a say as to whether or not they find this offer to be acceptable does not sound very democratic. It seems to suggest that only your opinion is allowable - which is rubbish, everyone is entitled to hold and express an opinion, the union must listen to those opinions if it wishes to carry out effective IA, something that BASSA has, as yet, failed to do.
Finally BA has already put UNITE on notice that it considers the latest reasons to ballot as continuations of the past IA and as such will have no protected period.