If you are a part of the 2008 section of the scheme your entitlement to a retirement lump sum will depend on whether you transferred to the 2008 section via Choice or not.
If you transferred to the 2008 section during the Choice exercise you must take a mandatory lump sum for your pensionable service up to 21 March 2008. If you opt to take partial retirement through Draw Down you can also Draw Down part of your mandatory lump sum.
If you did not transfer to the 2008 section during the Choice exercise and have solely been a member of the 2008 section since joining the scheme you do not have an automatic entitlement to a lump sum on retirement. You can opt to commute up to 25% of your pension benefits in exchange for a lump sum. If you take partial retirement through Draw Down you can also Draw Down part of your optional commuted lump sum.