So last Friday, the boot failed to open when I was loading shopping, so I dropped the bags on the back seat then checked when I got home and all was working.

Saturday it worked fine, then I drove 120 miles and again fine. Came back to the car a few hours later and it worked OK, then when I went back to the boot for something I'd forgotten, it wasn't working again. Tried middle button and boot release together and got it open to load my gear, but it has not worked since.

I ordered a new boot latch online (checking part against registration) and it arrived today, managed to remove trim and swap out the old latch opening it using the manual screwdriver method. Still no joy, so I've ordered a new boot release switch.

I've been unable to find a fuse that controls this particular item, so I've just made an assumption that the switch has failed. If this is not the case, do I have any other options than chasing the wiring around to find a fault?

I'm not sure why you started with the latch if it opened using the screwdriver hole but that's done and now you have switch so fit that and see how you go. You can check wiring at switch with a multimeter but if it's an intermittent fault it might be OK when you check but not later.

Wires inside the black plastic trunking, at the opening of boot door that takes wires from bodywork to boot door, can often be fatigued, frayed, broken, you could look there for any visual evidence.

Rust around the switch or rear number plate light might perhaps show water leak or corrosion in that area.

Have a look at posts and threads here on failing boot switches.

HTH.

Yeah changing the latch first was a schoolboy error. First time I’ve had a car with an electric boot switch that’s failed but had latches fail in Golf and Zafira in the past.

As you say it is what it is and I hope the switch does the trick.

Thanks for the tips on where to start if it doesn’t.

To update on this, found the fault. New switch arrived and i just plugged it in to test before swapping over fully, still dead.

Checked the wiring loom in the rubber gaiter near boot hinges and found that a wire had snapped and a couple of others were bent and at risk of snapping. Used electrician tape to shore up the bent ones and stripped the snapped on, then re-braided the cable (didn't have any solder in my shed) and closed back up with some heat shrink. Total of about half an hour's work in the end.

New switch will be going on eBay later today, keeping the new latch on the car and keeping the old one in the shed as a spare, because it will probably come in for either me or my son (also has a Fabia III) at some point.