I thought it was quite good, not hilariously funny all the way through but it had its' moments, particularly the scenes with George Bush and Thatcher, where Richardson and Saunders were both excellent.
No idea about Rik Mayall, but thought Jennifer Saunder's Mrs T as a cross between Marlene Dietrich and Miss Havisham was quite inspired. Also thought Nigel Planer's Mandy was rather good. It was better than I was expecting.
Jennifer Saunder's Mrs T as a cross between Marlene Dietrich and Miss Havisham
Actually, it was primarily Gloria Swanson-as-Norma Desmond, with a hint of Bette Davies's Baby Jane. The Sunset Boulevard homage was strongest (even to Tony floating in the water at the end!), although there was a hint of Psycho in having the mummified Dennis in the wardrobe!
I really should have been paying more attention Silverwhistle... Of course it was 'Baby Jane'.
I think I jumped to the Marlene Dietrich conclusion because I seem to remember Jennifer Saunders did a wonderful sketch of her many years ago in 'French & Saunders'.
The main influence was Gloria Swanson's Norma Desmond from Sunset Boulevard, though: the butler, Tebbit, was modelled on Erich von Stroheim's character.