Oh Fiona! You are such a gem! I hope they appreciate you!
Appreciate yourself and charge them for your time!
I’m in the USA where women are no longer a slave to linens or ironing.
We spray the linens lightly with a good spray bottle and smooth them out by hand. This works quite well and no one irons!
We recently purchased new duvet covers that are an all cotton brocade like material that wrinkles far less than the previous duvets that were more like a sheet percale.
We use all cotton untreated sheets and have never received any complaints. The beds may be slightly damp after spraying, but they always dry in time for guests.
Good luck and try some Wellbutrin. A lifesaver for those of us that suffer with anxiety!