Yorkiegirl - every pregnancy is an individual one so what happened before will probably not happen again. I presume you didn't have bleeding first time round?
Many women have clot development behind the placenta to varying degrees, often with no impact on the pregnancy. I would not expect any kind of treatment to be prescribed next time round TBH. Hopefully it is something that will no recur but you will not be able to get an absolute answer on that one from the obstetrician. Perhaps you could get an appointment with your consultant to discuss it? That is something that can be arranged at our hospital so I would expect yours to be the same. The GP will not have a clue IMO. I honestly think it is more likely to be a one off. HTH.