An increasing number of movies nowadays seem to be remakes or reworkings of TV shows so I guess the question is a little relevant.
I will start by saying that I think that Reginald Perrin could make a great film (or 2 great films) even now. The plots of those first 2 series are easily memorable enough to survive the crossover and as long as a movie could find a really talented cast and didn't take too many liberties then maybe it could work.