In the interim Chris give the plug surrounding area a good soak with release spray. Then before you try and remove it push a thin strip of soft cloth down there to soak up as much as you can as your catalyser won’t like being covered by the stuff!
BR
Colin (if you have a compressor and air gun or even an aerosol of air from a camera shop to blow around the plug to clean out debris it’s a good idea before you try and remove the plug).
