Check which terminal your flight is arriving into. BA operates from both Terminal 3 and Terminal 5. If both flights are T5 then fine however if you are arriving into T3 and need to transfer to T5 then it could be tight. There are connection buses so you don’t need to exit and re enter the terminals but will take additional time. Also if separate tickets then it’s unlikely your baggage will be checked all the way through. Sorry but lots of variables on this.