Battery tender leads

Here you go, picture where to connect the positive lead. This is the starter relay which is fixed on the battery cover. The big cable comes straight of the positive of the battery as you mentioned.

As mentioned above, just be carefull so the lead doesn't touch anything else but you won't get shocked.
For the negative find a good connection to the frame or engine.

Hope this helps.

Hi Mate, You could have saved a lot of hassle by using the accessory wires in the headlamp cowl. There are 2 sets, one switched and one live.