United Kingdom Stratford Butterfly Farm

I'm pretty sure this is the best butterfly house in the south of England (the new enclosure at Whipsnade Zoo isn't bad, but is much smaller than this). Stratford Butterfly Farm is cheap to enter and features the widest variety of species I've seen at a butterfly house in England. The only better places I've visited have been in Malaysia and Thailand.

It has winding paths through the greenhouse and so many butterflies that you can go for hours finding new compositions here if insect macro photography is your thing.

It has a caterpillar room in which I've seen some very cool specimens and a small reptilarium with bugs, snakes, leaf cutting ants etc. although in my experience that room is too dark for photography.

Give your lens a few minutes to adjust to the humidity once you enter (especially if it's cold outside) and take a microfibre cloth to give it a wipe.

Use a specialised macro lens if you have one, otherwise I've found my 80-300mm equivalent f/2.8 works pretty well (and its easier to compose if you can get further from the butterflies).

Don't bother with a flash, it's bright in here and you won't need it, and at close range you'll just end up darkening the background unless you're really good at blending flash and natural light (which I am not).

Focus on the closest eye. Sometimes it's easier to use manual focus and just move the camera as a way of focusing. Take way more shots than you think you need - most of them will be slightly out of focus if you're using a wide aperture with shallow DoF (or at least that's my experience because the butterflies and camera are both moving and a few millimetres either way makes you miss focus).

Most of the time, shooting a butterfly side on works best. To get an open wing shot you're mostly going to be shooting down from above, and you'll get distracting plants in the background. Look for compositions where the background is far away to ensure it blurs and the butterfly is isolated in the frame.

In post processing, turn the vibrance or saturation up to 11 - butterflies are colourful and you want to really show off those colours.

There's a public pay and display car park 5 minutes walk away. It costs about £6 for the day if I remember correctly.