If the flights are on time, you should have no problem but as you have two separate bookings, if you are delayed on your first flight you may end up missing your BA flight.

I know a lot of people book their tickets separately for many different reasons but as cabin crew, I would recommend that as your flights are not on the same booking, it would be better to arrive on an earlier flight, just in case of bad weather and you miss your connection. If you are on a through booking, you will automatically get looked after and rebooked but if not, you may encounter problems due to your flights not being officially linked.

Just my personal advice as I see these situations every time we have bad weather!