Any suggestions how to source a 'split' ring type anode for a Volvo Penta 130 saildrive at a cost below list? £31 plus VAT seems a lot for something that goes fizz!
Anodes are not the best place to start penny pinching. You could get a cheaper anode but would you be happy that it's going to do the job properly. A trace of iron in a Zinc anode seriously reduces its effectiveness.
Persoannly I would buy either OEM or from a well regarded anode company like MG Duff.
For the sake of £30 a year, do you want to risk thousands of pounds worth of drive?