In East Anglia, names with the structure X-ing-ēġ give modern forms in -gay rather than -gey (with date of first -a- spelling):
Bungay Sf (-ay 1235)
Gamlingay Ca 160 (-ay- 1271)
Shingay Ca 65 (-gaia 1087-93)
Wormegay Nf (-gai DB)
The only other -gay names in England (none certain to be -ing-ēġ) are Bogay Hall in Solihull (?cf. Bog Meadow Wa 347), Harringay or Harringey, Lingay or Lingey Ca 78, 119.
What's going on here? Was there an early pronunciation in /ai/, caused somehow by the -ing?