Pistonbroke, you are right about pushing the bike on a footpath but as far as I am aware it is not a criminal offence unless the council has passed a specific bylaw stating no pushing. Been a police officer for 15yrs and yet to see anyone done for that. We have enough on with motor vehicles and can deal with them, the only time I have seen a cyclist prosecuted was repeatedly hurtling round corners nearly killing old ladies on pavements.
Been wrong before but I think it is a civil tresspass matter and would be for the landowner to sue you in court for walking or riding on a footpath, assuming you gave him your name and address for the summons to be served. Police would only get involved if things got ugly ie; fighting. However common sense should prevail, respect for others and environment etc.