Colour me sceptical
This is a very small formation and they are claiming to have found a reserve 2/3 the size of the colossal Groningen gas field, more than 30 times as large as the Morecambe Bay fields and 10 times the size of *all* the reserves remaining in the UK sector of the North Sea. In each of these cases the reserves are known only by drilling a large number of widely dispersed wells into well-understood formations and long term monitoring. That's not possible here.
What's more, if they got a 20% recovery rate from this field they'd pull up very nearly half as much gas as the USGS reckons is economically recoverable from the *whole* Marcellus Formation in the Eastern United States which is almost the size of England.
I think a lot more work needs to be done before anyone thinks that Blackpool is sitting on a gas fortune. But in the meantime I bet that 200 trillion number is doing wonders for their share price.