Simple answer is - go there and assess the situation for yourself.
Although schools are constantly changing, this one is the largest privately owned school in the country. Being situated under the London TMA and in the busiest airspace in England there is a wealth of practical knowledge to be obtained. Some schools are so remote that often students are afraid to venture outside their 'secure' area and brave being surrounded by the complexities of the heavily populated airspace.
Hopefully, on either visiting the airfield or speaking to them you will be pleased by the genuine and friendly advise on offer
Although this is true of many 'flying clubs' because 'club' denotes a more personal message than 'school', a simple check with the CAA on their success rate should help you to decide. The CAA are not allowed to recommend or pass any other comment on individual schools. Also, only you will know whether or not the atmosphere there is one that suits you.