There are lots of existing threads on this sort of topic. In my opinion anybody investing for such a long period of time should at least consider a low charges unit linked (possibly tracker) fund.
I'm not recommending any managers. I go for one manager for ease of use and because they have a range of funds that meet my needs. I don't look at past performance. I look at the fund strategy/objectives and what they charge.
Also - don't forget index trackers where the choice of manager is (or should be) largely irrelevant since returns will be dictated by the index and not buy/sell decisions of the active manager.