Hey OP, I have just bought the same tablets- was taking the Wellwoman ones, but I think they're a consumer conspiracy! I'm continuing to take the combo folic/vitD Boots tablets for vitamin D even though the NHS pregnancy website says folic acid is only necessary for the first 12 weeks. I understand folic acid can't hurt, however.
There's no harm in carrying on. Folic acid is actually most important at the time of conception and the few weeks afterwards but will not do any harm to keep taking it. Don't pay through the nose for the expensive stuff though.