grandparents patrick and marianne charles , 78 and 74 , were without heating during a blackout on a cold november night last year .
the couple , who had been married for 53 years , sat down in their conservatory in eastbourne , east sussex , with a glass of wine each and fired up the barbecue to heat up the room .
the conservatory quickly filled with smoke and within minutes the couple were unconscious after choking on the fumes .