An update: This turned out to be not a big problem. To change the igniter, you need to remove the drawer under the hob:
- Open it and lift the rear of the plastic tray up and slide backwards; you'll now be able to clear the latch and take it out as a unit. Forks etc can stay where they are.
- Remove the two screws on the inside walls of the drawer. It then just slides out. When you re-install, just seat them. Do not tighten or they will catch in the sliders.
The igniter itself is held with a large nut that I was able to unscrew by hand. You need to find a replacement that 1) fits the hole and 2) has both the standard pin at the end and the secondary ground connector -- otherwise the rear burner will not spark.
A local propane shop had -- for 10 Euros -- a "universal 18mm or 22mm piezo" like available at
https://www.ebay.de/itm/18mm-or-22m...verselle-Nutzung-Pin-Verbindung-/232645139785 (photo copied here for posterity.) I needed to trim the long secondary connector.
The original is marked RV381 but I was unable to find a replacement that looked like an exact match. (no pun intended!)
Keep cooking,
Ted