I presume you are talking about the red stop/tail light and the separate amber indicator light.
If you really want "Original" and money is no object then Superformance http://www.superformance.co.uk/v12/lights.html
or Eurospares http://www.eurospares.co.uk/parts/fe...899/FLIG250/BR
will supply at a cost of £450 +P&P or £670 +P&P respectively for a set of 4.
More reasonably priced are the Lucas 539 (£136 +P&P from SVC http://www.s-v-c.co.uk/category/single-lenses/
) or the Lucas 691 (£91 +P&P from Europa spares http://www.europaspares.com/691-luca...ra-lights.html
You may well be able to get the same lights cheaper if you shop around a bit, plus if you look around the net there may be other lights which are suitable.
I have fitted the 691 lights on my car.