Stick with BAEC for now.

However, given the recent Avios devaluation, the ongoing fuel surcharges charged by BA, and the fact that you seem far off Lifetime Gold and might not even keep Silver, you might want to study AAdvantage's award chart. For most flights - apart from short haul - AAdvantage is a much better option than BAEC. Europe to Africa and Asia require much fewer miles with AA, and you have the added option of Etihad, along with the rest of Oneworld. BAEC is still best for short haul though. Depends on what you want to use your miles for...

You can also get a credit card in the UK that gives AAdvantage miles. Once my BA Gold has gone away after about 15 consecutive years, I'll most likely be switching to AA...