A penalty is to be treated as a debt owed to the Welsh Ministers.
The Welsh Ministers may—
charge interest on a penalty not paid during the period specified under section 50I(2)(d);
impose one or more additional penalties where a penalty is not paid during that period.
Interest and additional penalty are to be treated as penalty (and may have the effect of increasing the penalty above a limit set by section 50J).
A penalty notice may include provision allowing a discount if the penalty is paid on or before a date specified in the notice (falling within the period specified under section 50I(2)(d)).
A person to whom a penalty notice is given on the ground in Case 5 of section 50H may not be prosecuted for the offence by reference to which the penalty notice was given.