Storm Shadow missiles have a range of about 250km (155 miles), similar to the US Atacms, and have in the past been given to Kyiv by the UK and France to strike targets inside Ukraine’s internationally recognised borders.
This depends. The Storm Shadow/SCALP missiles Ukraine has, have had their range restricted to approximately this so far to comply with missile export controls and treaties. The domestic UK and French variants have an unrestricted range of around 560km/350mi, and there have been talks of sending Storm Shadow/SCALP missiles without restrictions to Ukraine. However, such a range could put Moscow in range of Ukrainian strikes, so I don't think the US/UK or France will give Ukraine unrestricted Storm Shadow/SCALP missiles, it would be seen as too large of an escalation/an unacceptable escalation. But crazier things have happened in this war so far...