Hard to advise without more detail about the wood, but generally I would think it best to support both of them independently and just fill the gap with an appropriate sealant. A forced marriage could end in tears, especially in a damps environment like a kitchen or bathroom.
If the oak is in the form of a wide board(s), be careful to allow it to expand/contract across its width, or it will crack. So if you were screwing up into it from battens underneath, then drill oval holes in the battens to allow the screws to move from side to side a bit as the oak board expands/contracts.
Never glue two bits of wood together if their grains are at 90 degrees, unless they're less than a couple of inches wide.
Thanks for your time and advice.. the oak is full stave 3m long and sold as a work top.
Its now got about 7 coats of oil on and looks beautiful !!!!!
I got it fixed today and like you said used oval holes ( slotted brackets )
I have decided to treat the two materials as separate jobs fixing them independently with a small amount of sealant.
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