Hi Ken
Sulphur/"rotton eggs" would indicate the catalytic reaction taking place, however usually this is most noticeable when the CAT is cold.
I would expect your car to have one being a 93 - it's generally a very flat 'center box' (although some elder types are quite cylinder) and with a little crawling under the car you should also spot the two sensors just before the two manifold ports concatenate. These are your O2 sensors. If you can't see them you don't have a CAT. ALL cars with CATs MUST have O2 sensors.
Interesting that mine hasn't though, being a '92, but hey - it's way cheaper in the long run! Typical dealer costs for these is around 800UKP each....yes...some cars are fitted with two!!
The typical exhaust configurations are shown on alldatadiy
Lea