The most important consideration when thinking about equipment is to pack light. You will need a daypack for hiking and a small duffel to contain your other gear. The duffels will be transported between accommodations.

The daypack should be one which is large enough so you can carry the weight on your hips. It is surprising how much stuff you need to carry even when it is just a day hike (see list below). I use my regular overnight backpack because daypacks are too short to fit me. You do not want your shoulders aching after the first few miles.

The other vital items of equipment are raingear and boots. Rain is part of the hiking experience in the U.K. I actually like the rain since it lays a light mist over the landscape and heightens your perceptions of your surroundings. However, it is not enjoyable if you are either wet or sweating from being encased in a non-breathable outfit. EMS or REI sells breathable rainsuits at a reasonable cost. I don't normally buy goretex simply because it is outrageously expensive. Lightweight boots that are already worn in are another vital piece of equipment. Waterproof them with nikwax or beeswax.

The key to clothing is layers. The weather ranges from cool and rainy to hot and sunny. You could be hiking in a cool rain in the morning and be in a tee shirt in the afternoon. Avoid cotton. It gets wet and stays wet. I use four layers: polypro base layer, shirt, trousers, jacket, and raingear. You can add or shed as you go along. I am including my list below. There is a * next to those items which are carried in the daypack.