Most people are looking to get to Silver or above as the benefits start being useful then. You don't get much for Bronze.
I would suggest that rather than try to retain base metal this year, you think about a plan for precious metal next year.
600 TP is needed for silver and that can be achieved in a single five night BA holiday trip to sofia from a regional airport (40+80)*2*2=480 with a side trip to a different UK airport included (40)*2*2=160 E.g. MAN-LHR-SOF-LHR-JER-LHR-MAN.
But you will need to look for cheap flight dates to keep the price down which means after your current year ends.
You can get 260 points this year by going on an exEU to the US, but it will cost you more and net you less IMO.