“They have been damping down hot spots and a re-inspection is planned at around 12:00.”
The incident in Eastbourne has now been closed, it added, after a “very busy night for staff”.
A West Sussex Fire and Rescue Service spokesperson said four fire engines remain on the scene in Thatcher Close, confirming the blaze was also believed to have begun following a lightning strike at about 04:15 BST.
Kent Fire and Rescue Service also said it was called to Newton Road in Faversham just after 03:31, and the fire was extinguished shortly before 04:30.
Another fire in Faversham was also reported in Uplees Road where four fire engines attended.
No casualties have been reported at any of the incidents.
Thunderstorms in the early morning came after a yellow weather warning for lightning was issued for large parts of East Sussex and Kent from 02:00 to 08:00.
According to the Met Office, thunderstorms are most likely to occur when the atmosphere becomes unstable, and “during periods of hot, humid weather, especially after a few days of strong sunshine, the ingredients for this instability are often in place”.
The storms come after days of high temperatures and red weather warnings for extreme heat.
Red warnings across the South East have been lifted, but an amber warning for extreme heat remains in parts of Kent, Surrey East Sussex and parts of West Sussex.
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