Stephen; my 2 cents worth:
Battery:
Mine is tucked away in the passenger footwell. No problem for me, but on a DRB it does restrict the passenger's leg comfort. Fine for short trips, but a longer journey would not be ideal. The boot idea is the best solution.
Oil Sensor:
I mounted my sensor between the filter and block using a bracket from Earl's. Ended up having to replace my Z9 filter with a Z39A (I think) as the standard filter would not fit. My temp runs at between 90 and 115 (depending if I'm standing in traffic). Based upon my readout I would assume (as per Cobber's comments) that the
oil was coming straight from the pump