Hello again True Owl,
Nice to see someone else from the West Country here. 😀
I think you’ve made the right choice with The Mabinogi, I too have Sioned Davies’s version and I’d highly recommend it. Another book I’d highly recommend as a source book or reference resource is Trioedd Ynys Prydein – The Welsh Triads by Rachel Bromwich along with The Celtic Heroic Age by John T. Koch and John Carey. I’m just about read (again) The Táin Bó Cúailnge, Ciaran Carson translation, I love this version and I never tire of rereading it!
By the way, “bennathow” is Cornish/Kereowek for “blessings” 😉