All back together and working well.
For anyone doing this , a few pointers: once you have the head off pay close attention to the 2 holes from the barrel leading down into the waterway under the power head !, pull the powerhead off and clean the waterways underneath it. check that the water tube in the leg is clear.
I also reamed the pee hole out with a 3.5mm hss bit.
Hope this helps others in the future.