Nowt to do with Town I know: But: Could some highly educated and enlightened person tell me who these "indigenous people" are please?
That would be the White, British people whose ancestors were here in the period 10,000 BC to around the last large-scale immigration in 800AD.
Historically flawed for several reasons I'm afraid.
Firstly, the ancestors of the occupants of these islands in 8000 BC would have moved here from what is now Africa over the preceding tens of thousands of years.
The earliest known settlements on what is now Great Britain, such as Skara Brae indicate likely connections with various parts of N. Europe, including Ireland.
The Celtic language group used during some of the period you describe share similarities with languages such as Hungarian, thus suggesting again a northward drift of people.
Between 55 BC (first Roman invasion) & 800 AD (your cut-off point) Britain was invaded numerous times, each occasion leaving behind non-indigenous residents who absorbed into the pre-existing population.
In other words...a) the population pre-8000 BC was not indigenous & b) it continued to be diluted during your reference period.