Hi. I've been adjusting the TV aerial on the roof. The roof ridge has a row
of half round tiles; the tiles are separated by about1 inch with mortar in
between.

I've noticed there are small gaps, around a millimetre, at the edges of some
tiles - the mortar has separated from the tile edges. They may have been
like this for some time or it might be because I disturbed the tiles
(walking/sitting on them).

The morter between the tles is in good condition and very hard to break. I
tried chipping away as I was thinking about cutting it back enouigh to try
pointing, but it is really tough.

Should I do anything about 1mm gaps? If so, is there a good way to fill
them without cutting back the existing mortar?

Thanks.