Well, sorry to be the bringer of bad news, but the double-yellow lines are sufficient on their own to define the restriction of No Parking 24x7. DYLs apply to the whole road and that includes footways and verges up to the property line. Whether you were causing an obstruction is totally irrelevant. We see lots of cases where motorists park off the carriageway where there are yellow lines and are shocked at getting a PCN. There may be a technical appeal argument based on council mismanagement of the enforcement process, or fatal errors on the PCN itself. Please therefore post all pages of the PCN for inspection.