New Ornamental Olive Tree Dead ?

Any ideas what has happened to our expensive new ornamental olive tree (wagon wheel shapes) ? Planted in November, healthy tree planted in new compost, now seems to be dead although it was sprouting new growth in January, not using anything different although new mother in law tongues seem to have bleached out also .

Overwatered? Are they in the ground or in pots?

How big /old was the tree when planted ? Why do you think it's dead ? perhaps a photo of the tree will help with suggestions.
Olive trees are fairly hardy trees & you have to something drastic to kill them,

We transplanted this 4’ olive tree straight from the garden centre to ground with new compost, watered sparingly during the cold months, gets lots of sun. Any ideas to bring it back to life ?

With your nail scrap back a bit of the stems starting at the top to see if there is any green under the bark ..if none that bit of stem could be dead repeat lower down ..do the same on a few other branches..the winter was very dry and warm so it may of needed more water until established...

Like Terry the gardener said keep watering, whilst compost is good for potting new plants it doesn't retain water well so dries out quickly, this combined with sparingly watering over winter is likely the cause for it looking dead.Olives when established can withstand temp down to at least -8 degrees even when wet.
New growth should appear from any cuts you make & if it starts growing suckers from the roots don't cut them off,let about 3 or 4 grow & see which is the strongest then keep the strongest one & remove the others as the remaining sucker will grow into a tree eventually.

Thank you all for your advice. I have done a scratch test and everything is green underneath despite all odds. What would you recommend to restore this to its former Glory without under or over watering please, grateful for any tips, thank you.