Your car is the same age as mine (1991) so pre dates any necessity for CATS in the UK. I've never ran mine with CATS until this year & it never failed an MOT, as the test is a visual check. The only reason I've fitted some free flowing CATS from Pride, is to reduce noise as I've got a Tubi exhaust fitted. They didn't really make any difference to the noise than the Pride resonated test pipes I had previously fitted.

As Kaz says, you shouldn't have the secondary lambda sensors, so nothing to worry about if you remove your CATS.