Q.Roots causing drain problems
I had my drains cleaned today and the drainage was impeded by roots. It could be a 40+ year old Wall Ivy or a 40+ year old Yew Bush growing down to a depth of approx. 5-6 feet to the drain pipe. Which is likely to be the problem or could it be both please?
Ray

While the root systems of different yews vary, many have deep, widespread roots that become dense.
An ivy plant has two types of roots. The subterranean roots extend into the soil, attaching the plant to the ground and absorbing water and nutrients from the soil. Clumps of adventitious or aerial roots are located at intervals along the climbing stems. The function of these roots is to attach the plant to a surface as it climbs.
Whether either of these two plants are the cause of your drain pipe issues, is beyond my expertise.