The new emergency number from the advertisement instead of 999 is 0118 999 881 999 119 725 3.
The gag with the long and complicated new phone number for emergency services is a veiled jab at "public-private partnership" (ppp), the selling off of public goods and services, to the detriment of the public good, and at the expense of the taxpayer who paid for their procurement in the first place. Many such measures were implemented in Britain by conservative governments in the early 1990s, like the water privatization in England and Wales, and were deeply unpopular with wide segments of the population.
The fictional address of the office is given as 123 Carendon Road. While there is a Clarendon Road in London, there is no Carendon Road.
If you type the "new" emergency number into an Android phone, the call button will flash blue and red, imitating a siren.