Not tried the speed pump, this is in the boiler which is new from last October; the new pipes go horizontal across from existing bathroom rad 15mm flow and return pipes then go straight down to new rad on kitchen corner below.
Water pressure seems pretty good as gets to bathroom towel rad, which is highest point of system. The rad is newly new but have flushed it out with hose, no rust or dirt in it.
I have taken out the one way flow valve as I didn't like having it in for nothing or making situation worse. Haven't come across wire wool, unlikely as we cut up all the pipes manually at home from 3m lengths.
What do you think of going straight from 22mm pipes to new rad ? Would this make any difference ? It might have more pressure than from the 15mm rad extensions ?
I traced the two 15mm feed and returns to the bathroom rad and checked where these two feeds came from to make sure it wasn't connected wrong way round ie flow to feed and return to flow. I traced them to the main 22mm pipes and they are from diff pipes not the same.