A fast fit centre should do one of these for less than £200 - start with a quote from a Ford Rapidfit centre, they are usually attached to main dealers, but are cheaper.

As it sounds like it is on its last legs you may as well replace all of it.

Until recently I had a 1998 Fiesta with the 1.3 Endura-E petrol engine, I'm not sure if this is exactly the same model that you have. Even with the 1998 Endura-E, Ford fitted more than one kind of exhaust system.

My experience of exhaust repairs was:

The front section, which includes the catalytic convertor and exhaust manifold, costs about £250 including fitting. Lasted about 10 years on my car.

The middle section, which is flexible, costs about £150 including fitting. Lasted about 8 years on my car.

The rear section costs less than £100 including fitting. Lasted about 4 years on my car.

Depending on exactly which model you have, the prices might be different.