You will probably also pay around £50 more for a BA code. Just looking at January the fares start at £88 for a BA code and around £38 when sold by EI under their code. This is more or less in line with the prices that I have seen before on this route.

This is in the lowest booking class (O) so would earn 5 TPs. It obviously depends on individual circumstances and how much you need the TPs as to whether it is worthwhile paying the extra for the BA code.