Hi red, I remembered to ask the NICE midwife I just saw lol She says it is perfectly normal to get a congested feeling when having a BH and theres is nothing to worry about. If, however, you get the blurred vision/lights in front of your eyes, let your midwife know. But you know that anyway.
As I see a nice midwife, I got all my home birth forms signed and sorted so thats one less thing for me to worry about! Babys head is "very engaged" and baby is right down in my pelvis. She has said, although possible, it is very unlikely it will move now as its well and truely in there!