>>> "We cross reference the information you provide on your order form with information on our databases (these are not publicly available and we have to be licensed by the CSA, OFT and ICO to use them)".
Just because companies say that they're licensed by government agencies, doesn't necessarily mean that they actually are!
As an analogy, if you're looking for cheap Microsoft software, there are hundred (or possibly thousands) of websites offering it for sale. They all seem to carry a Microsoft logo, together with wording such as 'Authorised Microsoft Dealer' or similar, but none of them are actually trading with Microsoft's consent or approval. They simply say that they are.
I'm unaware of any licensing system offered by the ICO and I can find nothing on its website to suggest that such a system exists. Further, the uses to which the full version of the Electoral Register can be put are stated on the Gov.uk website and don't make any reference to private companies such as those who claim to be able to trace people:
https://www.gov.uk/electoral-register/opt-out-of-the-open-register
My scepticism about the advertising claim quoted by TCL deepens even more when considering the claims that the company is licensed both by the CSA and OFT. The CSA was closed down in 2012 and the OFT ceased to exist in 2014!
Don't get conned!