Parked on double yellows

A car garage on this street have recently moved in and are now taking on loads of car work which is fine but they are now double parking on the roads stopping deliveries coming onto the street parking on double yellows but then put tape on half of the registration plates so the traffic wardens dont do anything about it and also right outside they have got several cars parked all the way across the path with not room to even walk o. Let alone have wheelchair or pushchair access. We have contacted the council traffic enforcement but they said as they are covering the regs with tape there is nothing they can do and it is a massive nuisance for everyone but no one will do anything due to them taking the regs