This query will search for reg keys that indicate your Sophos agent requires a reboot to complete installation/updates and the date it was flagged to be rebooted
WITH rebootRequired AS (SELECT
CASE
WHEN data LIKE '1' THEN 'Yes'
ELSE 'No'
END AS RebootRequired
FROM registry
WHERE path LIKE 'HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Sophos\AutoUpdate\UpdateStatus\VolatileFlags\RebootRequired'),
rebootRequiredDate AS (SELECT datetime(CAST(data AS unsigned_bigint)/1000,'unixepoch','localtime') AS RequiredSince
FROM registry
WHERE path LIKE 'HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Sophos\AutoUpdate\UpdateStatus\VolatileFlags\RebootRequiredSince')
SELECT RebootRequired,
CASE
WHEN RebootRequired = 'No' THEN 'n/a'
ELSE RequiredSince
END AS rebootRequiredDate
FROM rebootRequired JOIN rebootRequiredDate