The ignitor on my gas oven in the caravan has stopped working switch works but no spark, I have read ot could be damp but I don't think it is, I think it's an age thing can it be replaced 🤔
Firstly, the good news is that cookers change very little from year to year and parts are often common for many years, therefore a pretty good chance spares are obtainable.
If you can identify your cooker a little better, the user manual will be available for download from the internet (maybe even Thetford (Spinflow) themselves), which will tell you if the igniter is a battery powered one or 12v system powered one. https://www.thetford-europe.com/gb/products/cooking-appliances/cookers
Certainly true, Piezo igniters can be a little fickle in cold/damp conditions. You may not actually have a failed part, just incompatible environment at the moment. Try lighting the oven with a long reach BBQ type lighter (or good old fashioned spill), and let it heat for a while, then retry the Piezo lighter once it's warmed up a little.
Thanks for all the info it didn't work over the easter weekend we lit the gas using a bbq lighter and i thought that the regular use over the weekend would have dried it out, I'll find out more info about the cooker and download manuals or I fo to help me. Thanks for your help Monty 15 much appreciated.