I have an area of garden that has been covered in bark chips. I now wish to
level and raise it slightly with a layer of top soil prior to seeding as a
lawn.
Will it be OK to cover the bark chippings?

If you want, but you'll need more N for the lawn.
On the other hand, it's easy enough to rake them up and compost elsewhere.


If this is next to the house, do be careful about raising the soil level --
it can provide a convenient pathway to the house for termites and similar
insects. A minimum of 12" between ground and siding is required in
most US building codes, iirc. May be different in the UK, but it's easier
to keep a good gap than deal with insect damage, imho.

Kay