Meanwhile, my wife has had a summer house built at the bottom of the field and we've just picked up a VTOMAN FlashSpeed 1500 Portable Power Station to give her power down there. It will take up to 400w of solar directly into the box as it has an in built MPPT controller with a minimum voltage of 30w.
I have two 80w panels that have been sitting around for a while and I've just hinged them together and need to wire them in series to give the required voltage. Now, in the connector box there are two connectors each for +ve and -ve, with diodes in between. I'm connecting positive from the other panel to the negative terminal and then out again from the +ve, the negative lead from the other panel is joined in the box to the negative going out to the battery box. Here's a picture that I hope will make more sense of my description.

Question is, do I connect one or both of the positives on the diode input or output terminals?