I already use powder straight into the drum rather than in the drawer (thanks MN!).
What else can I do? Am thinking:
*Monthly hot wash with vinegar/soda crystals
*Clean out the seal (with bleach?) to prevent it getting gunky
Where I live the water is awful, really hard. Have to descale the kettle every few days (even using filtered water) so...
*Anti-limescale tablets with every wash
Any other top tips?