ESP32 WiFi/Bluetooth problem

I’ve just upgraded from Arduino 1.0.2 libraries to 1.0.4.
My application (On a HELTEC kit32 with OLED) talks to a BLE OBD sensor. It is configured as a large app (No OTA).
It also has an SD card attached, a GPS on serial, a BME280 and a 9DOF device on I2C and finally an IR sensor with remote keypad.
It all worked fine on 1.0.2. APART from : When I finished logging data and came to email (using smtp2go) the file from the SD card, it would lock up for 8s seconds at a time on client.write() statements completely at random and cause smpt2go to close the connection.
I use CORE 1 for the main loop() and CORE 0 for writing to the SD card. There are no writes to the SD card when trying to email.

On 1.0.4 libraries, I can no longer connect to WiFi once the BLE is running. If I connect to the WiFi first, then when I try to do a readValue() of a characteristic on the BLE device, the ESP32 hangs. It doesn’t crash. It seems to be waiting for a blocking semaphore on
readCharEvt().
Does anyone have any ideas? I know it’s a complex situation and usually I can solve my own problems, but this one has me stumped. I have already tried on the esp32 forums with no joy.
I can’t find any way of just disabling the Bluetooth while I do the WiFi stuff. (I understand they use the same antenna and RF circuitry). I have reverted back to 1.0.2 for now as 1.0.4 just kept generating random core panics…