There's a throwaway comment on the movie industry; they sometimes call extras 'moving scenery'. Here, they're the scenery that gets chewed by many of the cast.
This is such a hodge podge. Occasional scenes are ghoulishly funny, riffing on the cliches about 'older people' and the younger crowd; and, of course, the many tropes abounding after 60+ years of mainstream zombie films.
The third agers- Anita Dobson, Sue Johnston leading - have the, erm, 'meatiest' roles here; plenty to get their teeth into! Others, including Robert Lindsay and Michael Smiley, are good but initially peripheral.
There are many scenes that some might prefer to 'unsee'; there is a taste (!) of the 1960s Hammer horror classics that goes way beyond what was possible then.
Where it falls apart is the multiplicity of characters, generations and their stories. It needs three generations; school age, pensioners and that 'squeezed middle'. There ends up being such a muddle of characters, quite diverse, so that by the time you've worked out who is related to whom, they're toast; with lots of extra strawberry jam.
One final problem for the school agers; some decent acting here, but a couple are still in sixth form aged 28 and 26, and there's no acting around that fact.