Somewhat garbled definition of this (British?) term courtesy of Devivo Homes:
"Bungalow gobbling has become very popular in the recent times. This is owing to the fact that the price of real estate has been on a steep rise and there are no signs of it decreasing soon. This makes people think of ways to buy their dream home and yet stick to their budget. Bungalow gobbling seems to be the perfect solution to their problem.
The price of buying plot and building a new structure on it is very high, and not to mention it is also full of hassle. Therefore people buy cheap houses and then modify its structure to turn it into their dream home. For example, you can increase the height of the ceiling, build a new adjoining room, and enlarge a particular area."