Yeah there are quite a few smaller hybrids, but none that i can think of that flower in the summer.. there are a few yellow ones that flower in early autumn but they're normal size.

I'm new to Orchid growing, so have no real suggestions of which plant myself, but have found this site which has a few links to Orchid Suppliers based in the UK. This may help with acquiring plants suitable for the UK climate.

North of England Orchid Society - Nurseries in the UK

Don't forget about Zygopets! They are cool growers,will flower throughout the year and most have an excellent intoxicating fragrance too!