I've been hanging out on another forum (sorry John!) and found a couple of useful alternatives if you usually rely on Royal Mail.
UK Mail (formerly Business Post)
www.ukmail.biz - If you are sending quite a few packages every day you might be able to get a good rate with them, and it's next day delivery, although someone commented that they are good for delivery to business addresses but not so good for residential. I also don't like the look of their t+c - there is a charge for redelivery if the recipient is not in on the first attempt.
www.myhermes.co.uk - A company I've never heard of before but I think I will try it out. For parcels less than 2kg they are offering £3.47 + VAT which compares favourably with the price I'm getting from Royal Mail, but it's a 3-5 day service which is not great.
Rob