And the results are in...

Example of maximum daytime temperatures recorded at contrasting slopes in the valley, compared to regional Met Office data from Exeter Airport, in summer 2014. 

Example of minimum night-time temperatures recorded at contrasting sites in the valley, compared to regional Met Office data from Exeter Airport, in Spring 2015.  

All the datalogger sites recorded average temperatures slightly warmer than those recorded at the Met Office weather station at Exeter Airport at Clyst Honiton over the study period.

Variations within the valley in which Easterbrooks sits were as predicted by the model: south-facing slopes were, on average, warmer than north-facing slopes, and the valley bottoms were cooler than the valley sides and tops. Air temperatures at the logger on the north-facing slope were, on average, 0.3°C warmer than Exeter Airport; the logger on the valley bottom was 0.7°C warmer; near the bottom of the south-facing slope it was 0.9°C warmer, 1.8°C warmer at mid-slope and 2.0°C warmer at the top of the slope.

The conclusion? The south-facing microclimates on slopes at Easterbrooks are likely to be suitable to produce a yield of some Mediterranean, warm-temperate and even subtropical crops, but the warm microclimate in itself is unlikely to be sufficient to produce a banana crop due to the long, cool winter season. Further artificial modification would be necessary in order to extend the growing season further.