-on-Sea or not -on-Sea?

[Mikeyd2]

Just got back from a visit to the coast and wondered why some places have ***** -on - Sea and some don't?
For example there is Westgate-on-Sea , Burchington-on-Sea in Kent next door to Margate , where's the -on - Sea bit etc?
Or Bexhill-on-Sea near just Hastings in Sussex, you get the picture .

Just curious.

[Catso]

In some instances, the "on sea" was added to try to make the place more attractive as a holiday resort.

In some it may be to differentiate between it and a similarly named place nearby.

In others that is just what the place is called - full stop. Why are some places called Hastings and some not?

Burnham (Somerset): it was added by the railway company in their efforts to develop the place as a resort.

[aristotle]

I could be wrong but I think the "-on-sea" places are Victorian inventions or at least developed as seaside resorts in the Victorian era whereas the others have been around a lot longer and had signifcance before seabathing became fashionable.