On the heat issue, Poppytoast, Gilla, Pippa - agreed, there's said to be something called oestrogen dumping that occurs when patches get overheated. Some years ago I was advised to remove my patch before MRI & when I asked why (MRI was head & neck, patch on butt, so seemed odd to me), Radiology said because patches may get super heated during MRI, causing them to release excessive amounts of oestrogen . . . affecting symptoms. Can't find any studies to back this up today, but would be interested if anyone knows of any.
For that reason I take care not to allow my very hot shower water to blast my patch directly, though hot water still runs over it of course. Might be worth experimenting Gilla, if you can swap the v hot bath for a shower that gives you a bit more control over heat potentially affecting patch release.
Wx