Transfer Or Not
CGAN,
You've pointed to some of the considerations, such as what are the charges on the existing contract? can you get better elsewhere without an entry charge?
Diversification between providers isn't a bad idea - a point in favour of leaving it where it is.
On balance, chances are you'll be better off leaving it where it is - assuming it's not with a fund manager with a consistently poor track record. (goes against AAM teaching I know, but I know where I have my pension - with a consistently strong fund manager, not a consistently poor one.)
If it was set up by your own company - probably no reason to switch elsewhere. If it was with a previous employment, then there are different considerations.
Maybe if you got back with the fund name, provider and annual management charge I could be more specific.
Benny.