So, baby has definitely 'dropped'.
Monday, Tuesday and Wednesday I had period/stretching type pains/aches. I was up a couple of nights vomiting (from severe heartburn more than anything I think). Since Thursday I have had severe lower back ache, and my pelvis is killing me (to the point I've had to take sick leave from work for next week before my maternilty starts). My bump is definitely lower, and my breathing much easier, and I can now eat a full size meal again 
This is my second pregnancy, and the only information I can find says that in first pregnancies this happens up to 4 weeks before labour begins, but with second pregnancies it happens much closer to labour starting (as in hours before or during) 
Does anyone have any experiences of 'dropping' in second pregnancies?? If so, please share!! Tia.