Thats an MG Sport'n'Racing part that... not seen it for general sale though, only on some of the competition cars.
It looks like it will only fit the '01MY' cars though, as it would require the removal of the front lip spoiler before fitment. The bumpers were change in late 2002 for the '03MY' cars to make them an intergrated part of the front bumper, thus anyone with an '03MY' car would also need to source a Rover 25 front bumper to fit it too.
'01 Model Year' cars are cars registered from launch in 2001, until late 2002 (november-ish), when the first '03 Model Year' cars came out until the mk1 ZR ended.
Unless your car is an early 2003 registered car (52 plate) it will definatley be an 03MY car. 2003 '52' plates are likley to be '03' spec but some 01 spec cars were still sitting about and thus registered later than the rest.
03MY has moulded front and rear bibs on the bumpers, as well as the moulded rear spoiler with the extra fin. Internally, the heater surrounds got new heater graphics, cup holders and cd storage appeared in the door cars and the strip from the dash facia above the airbag/storage area was deleted.
NB - the car in the picture is actually a Rover 25 anyway