Bob. You beauty. Another rescued machine, so therefore confirmation that it fixes this issue on the Beko WDIR7543101 integrated washer/dryer.
I took the liberty of taking a series of photographs, and made a brief guide below. This is just my experience, and I'm not a qualified electrician / white goods repair man, so you follow this guide at your own risk!
1. Drag the machine out on some cardboard! Make sure to isolate and unplug the device from the mains, the water and the waste before undergoing any of this work.
2. Remove the 5 screws from the rear
The black box is located here at the bottom right
3. Remove these two screws to loosen the box
4. A piece of sticky foam holds it down, so run a knife along it to separate.
5. Carefully jiggle the black box out and make sure you de-clip the cable holders from the machine (circled red below) to allow you to move the box. The front cover just slides off to reveal the board.
6. Now it's out, carefully unplug all connectors
7. Gently lever the board out of the black box #
8. Replace this diode (D7) - see Bobs recommendation. I personally used these.
9. Reverse all of the steps above, and turn on!