I use self trade for my child's CTF. I use the self select option. There is no annual management charge for the self-select CTF. I only pay for trades (£12.50) and from August 2010 CTF's can use the regular investment option (£1.50 per trade, minimum £50 per month) but there are limited investment options for this: FTSE 100 companies, ETF's, ETC's, Investment Trusts and about 50 other Funds.
Choosing your own investments is risky but I've tried to make it relevant to my child so that they stay interested over the years e.g. Bloomsbury (Harry Potter), Hornby and Games Workshop and once a year we write a letter to the Chief Exec of the companies in which they have invested and we keep a copy in her investment folder - so far we have never had a reply!! C'est la vie...