3 Quotes and they are so different in content and cost, how do I know which one I should opt for, I don't undertand the terminology so feel baffled with science............. The roof appears flat but it is actually a gully, old copper is still present, continuous problems, water outlet pipe on our side of the building, all three state this will increased to 75mm, one states Code 5 with 2 T-pren expansion joints, seal junction with neighbour using flashband and elastogum, no guaranteed because there will be a joint, other states strip out and overlay timbers with one layer geotech underlay felt and mark outline of new bays with timber straps, dress code 5 cut out raggle above up stand and supply and fit new lead apron touched and secured in to raggle ( what is raggle?) Other states uplift existing copper gutter and alter gutter base to form stem for lead cutter, install 2 code 7 lead panels to gutter, DPC to wall head and rebed, Can anyone tell me what is the best option to go with, I want to be problem free...............Urgent replies appreciated