read this site
http://www.parkingticket.co.uk/em.html
check the lines are legal for starters
http://www.ticketbusters.co.uk/
If you are in any doubt you should appeal. Local Authorities do not like you to appeal as it costs them time and money.
THINGS TO CONSIDER…
If you do wish to appeal then do not pay the charge.
If you pay the charge the council will close the case.
It is worth remembering that in most areas, the 50% discount on your PCN is preserved within the initial 14-day period.
You therefore have nothing to lose by appealing against the issue of the PCN.
Most local authorities will give you a further period to pay, should they not accept your representations (please note that this does not apply to tickets issued on Red Routes).