1. Make a backup of your wallet file!...
2. Put the COPY into the Bitcoin Core datadir
3. Start Bitcoin Core with commandline argument -upgradewallet
Hopefully, that will then allow you to dump the keys etc. If that doesn't work, then PyWallet might be able to dump the addresses/keys.
One last thought... Are you 100% sure this is a BITCOIN wallet? Any chance it could be a DOGE or LTC wallet or some other altcoin?
Thanks HCP I'll give that a go.
It's not an alt wallet, it predates LTC and DOGE by a fair bit The laptop has been at the bottom of a moving box for ages. It's just an exercise in claiming dust on BCH and BTC chains before their tx fees grow.