Puzzle with an extra twist . . .

[cinnabar]

. . . the twist being that the answer has to be entered in jumbled form, and the subsidiary part of the clue refers to the jumbled form

Old limestone radical, not quite apologetic, follows in May hoofer (12, two words)

So far I have _N_AMRED__RR and I reckon that
radical = red and
not quite apologetic = sorr(y)
Which would mean that the above becomes _N_AMREDSORR

At which point I get stuck - can't get anywhere with the May hoofer bit

Please can somebody put me out of my misery and suggest either the missing bit of the subsidiary, or what the old limestone (assuming that is the definition part) might be? All suggestions gratefully received . . .

[kayakamina]

Could the first 5 letters be IN MAY ( hoofed around) ?

Making Inyamredsorr - anagramatised to give a two worded definition of Old Limestone?

[cinnabar]

Thanks for the suggestion - unfortunately the clue definitely says hoofer rather than hoofed, and this being a Crossword Club puzzle a nounal anagram indicator would definitely be frowned upon (though a misprint is always a possibility)

Also I have tried putting the combination you suggest into a couple of anagram finders without any success - I have a feeling this is an old name for limestone which is no longer in common parlance, and I am going to struggle to find a geologist who can help!

[Catron]

Ok I'm not sure that this can be right but what if the radical was rebel and not quite apologetic was just sor - I cannot see the rest of the wordplay but Forest Marble is an old limestone. Just throwing it out there.

[cinnabar]

Once again, thanks for the suggestion - unfortunately I am quite sure that the letters I have got are correct, and that the answer needs to have a D and three Rs in it. Shame though - forest marble is just the sort of traditional name I am looking for!