Afraid that is so, the £80 is a statutory amount that everyone gets fined for not declaring SORN even if the car had not been on the road, you either have to tax it or declare it SORN to avoid that charge.
The court then seperately can fine her the other amount because the car was not taxed and has been seen on the road & reported, perhaps they have included back tax or court fees in their fine, but yes they have legally got the rights to charge her. Look on the bright side they could have confiscated the car, put it in the pound, then sent it to the crusher.

HI, my partner was fined 80 pound last year for not declaring her old car SORN. the same car was sent to court for being parked on the road without tax on it. the court fined her a total of 194 pound. but when she phoned up to pay the court fine she was made to understand that the total charge is 274 ie (80+194). pls i want to know if a car without tax can incur two separate fine for not declaring SORN and being parked on th road without tax.
zizzy