might not bee too bad for you- they have removed some of the price breaks for small items- a 750g parcel costs less after the end of the month then now. But whereas you used to be able to get a rate for 400g, for example, it will now go into that 750g which might be more than you were. paying.
I dont know how heavy your packages are, but I too send out a fair few packages of small parts, but not enough to warrant franking. Some could go by courier, but it is a pain to be in all day waiting. Most are £2 to £3 to post. The worst hike is for bog standard letters- the rises on the rest are only a few pence.
I was fearful when I first heard about it, but although it is frustrating, it isnt worrying me too much.