In case you are not traveling a lot, i don't think you should push on getting bronze. I was traveling a lot in the US with AA so in this case i did like the benefit of not having to pay for my suitcase as a BA Bronze and being able to select exit row seats for free 24hrs before departure. As you are based in the UK you won't get much out of you benefits, besides earlier boarding, group 4 as I remember, and seat selection 1 week before departure.
If you get a good deal and you are traveling anyway, go for it. Otherwise, as stated above a couple times, keep the money and spend it next year to get silver, if you plan to travel a little bit more.