wallet retrieval – 18-word mnemonic seed containing words external to BIP39's word list, which struggles to recover BTC

I have recently retrieved a document containing information related to some BTCs purchased in 2015. I only have: a passphrase / password, a mnemonic phrase of 18 words (most of which do not appear in the word list BIP39, neither in the old word lists / new electrum, eg mccartney, hopkinton) and the address: 1CfadqyBDRPt62S9UvBHDPtqRu2kSvwPPu.
I sillyly forgot to add the wallet that I used, so I'm a little stuck.

Any ideas on what the mnemonic could be?