3November - if you have the hours then apply now - you don't know when they will change/up them. When I applied then had a min hours OR min sectors requirement. Being regional I only made the number of sectors - by the time a few of my mates got round to applying they had dropped the sectors requirement and so they no longer made the eligibility.
Also as I am sure has been mentioned before - seniority is king in BA. The date you start will affect your fleet / time to command and even your roster till the day you retire!
The assessment day has nothing to do with flying hours anyway - worry about the sim when you get through that.
Also - if you are set on BA they seem to have a year between applications; so if you do flunk the interview it is going to be quicker before you reapply.
Just spend some time on the 'essay' questions on the application - and I mean possibly weeks not hours - that is what gets you a face-to-face. They have guys with 500 hours on Tubo props some with 2000 on the airbus and they are used to integrated students going striaght on to the 'bus with 200 hours. If you have got to the stage where you have flown a 319 at all then you are fine!