Hi, I've got a leaking / not working internal stop cock which I need to replace. The pipework between the internal stop cock and the street stop cock is lead and I don't fancy digging a trench etc and paying Thames Water to connect new plastic pipework. The pipework from the internal stop cock internally is copper. Can I cut the old lead pipe close to the stop cock and connect one of these lead to MDPE couplers? http://www.toolstation.com/shop/p74879 Then connect 25mm pipe through the sub floor void in the hallway and then below the new screed that will be put down in the kitchen and then connect a new internal stop cock in the kitchen? Also, does the MDPE in the floor void need to be lagged / insulated / boxed in something?And how should I run the MDPE under the screed - in the insulation or chase out the screed afterwards? Thanks in advance.