So, for instance, (just talking ‘BT’here)
0118 = a very large area based around Reading
0118 969 = a line from Woodley exchange (in Reading)
0118 966 = a line from Earley exchange (in Reading)
So it is the prefix and the first three digits after that show the exchange of origin.
Yes, there are lots of exceptions to this very basic rule, and even at the same exchange there are a variety of ‘post area code, first three digit’ offerings, 944 is another common for the Woodley exchange.
But essentially, if your new address is served by a different exchange, the answer is going to be - No.
All this will change once PSTN disappears sometime around 2025