Today I pushed pushed my bathtowel down the side of the bath so the resident spider could get out - does this?

That is so cute! (sorry if you don't like that description). Spiders probably curse the day baths were invented. Good on you for helping the poor little thing out! I've done the same kind of thing for other little creatures in precarious situations - usually involving these unnatural houses that we've built on or near their homes. Perhaps one day they will have adapted to our intrusions on the environment and evolve that ability... Hopefully with our speed of progress, there won't be something worse for them to have to adapt to by then ;)