Shares in ITM Power have rallied sharply lately, but broker Panmure Gordon sees room for much more growth and lifts its rating on the developer of alternative fuels to 'buy' from 'hold'.The firm has had a few technical difficulties, but these have been resolved and a deal with a blue-chip customer would help improve perceptions of the company, Panmure said.'Clearly there is a lot to do, but the company has a strong balance sheet and is now fully focused,' the broker said.It now has a 50p price target on the firm, from 20p previously.