If he is eating and drinking, the area isn't bleeding heavily, and he is well in himself I would agree with applying antiseptic such as iodine like you have done, which will prevent infection and allow healing.
If he was unwell, or in any way struggling to breathe, regardless of bank holidays I would advise getting a vet to visit asap (all vets should have a system in place for 24/7 emergency cover) as the histamine released by insect bites is essentially like a big allergic reaction and may need immediate treatment to prevent his airways closing up.
Hope he has learned his lesson and feels better soon!