Is it possible to block a range of phone numbers
as I keep getting accident companies and personal injury calls.
I have read that these are fake numbers for use in TV and radio dramas
There's no functionality built into Android to do this. If you want to block a range of numbers, or numbers matching a pattern, and you can't install apps on the phone to do it (as per Can I block calls based on a specific number prefix or pattern? or Free app to block calls and SMS based on pattern), then all you can do is contact your carrier and hope that they can set up the block for you at the exchange. Carriers tend to be quite obliging about blocking nuisance callers, but of course they too may be limited by what software they have available, and they may just tell you to use one of the apps mentioned in the linked questions.
I know this question is from 2 years ago but in case anyone is still wondering about this, I can say that at least on old LG smartphones like mine (LG Magna, also known as LG Magna H502F, H500F), it has built-in number blocking functions, and there you can block specific numbers, numbers that begin with the digits you specify and numbers that end with the digits you specify:
Android Version: 5.0.1
UPDATE September 2020:
I have had two more LG smartphones (LG Q6, LG K51S) and they also have this same blocking features. Seems like this brand always have that function in their android systems.