It’s working! As far as I can find, this is the first example of an MCP2515 CAN SPI module working with an ESP8266.
Previous post on my setup with ESP8266 and MCP2515
I have just bought another ESP8266/NodeMCU development board cheapy from eBay (this one) with an ESP-12E chip on board. I’ve also bought an SPI-CAN bus interface with the common Microchip MCP2515 CAN controller to try and create a CAN-Wifi gateway.