A.Lee wrote:

Trouble is, I cannot drill into these posts to screw in the cross
battens. Invariably I get in half inch or so, hit a stone, then the
drill rapdily goes blunt, and goes no further.

It may be that you are hitting steel reinforcing bar in the post rather
than a stone.

It it were a stone, a SDS drill and bit would romp through it easily.

If it is rebar, then you can get rebar cutting masonry bits that ought
to do the job. (Just positioning the hole in a different location will
probably help you miss the rebar).



--
Cheers,

John.

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