You need to make up a flylead like the one shown by a charger in the photo below. This one I made up to connect the charger shown to two different connectors. Basically it's a cable with a connector of the opposite gender to the one on the charger on one end, and a connector for the Powatryke battery charging connector (almost certainly the smaller one) on the other end.
Only two wires are needed in the cable, positive and negative, so you will need a meter to check which is which at each end and connect accordingly.
I cannot know what the connectors are without seeing them, the one you call a phono won't be, it's probally a microphone type connector like the one at the l/h end of the flylead in the photo. You should find the right connectors by looking in those supplied by
Maplin through their local shops or mail order, but if you can photo the connectors and display them here we can help with the identification: