If you transfer all your ISA stock holdings to Hargreaves Lansdown under the Vantage Scheme, they will handle all the transfers for you. Frankly, if some of your funds are performing badly I'd move them all now rather than on a drip feed basis, especially as signs are that the stock market could perform well in 2011 despite doubts about the economy.
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Hargreaves Lansdown are efficient brokers to deal with. Once you have an account with them your equity ISAs will enjoy a loyalty bonus and you'll be sent regular reports on how your funds are performing, recommendations on bad ones to ditch, and regular literature about all the funds which are available. Plus their website (www.h-l.co.uk) has lots of information on all the funds available and their performance.