Just one word of advice - I have seen this before.
Sometimes a company and a name can be two different things. I have seen "John Doe" trading as Bloggit tools, and then "John Doe" as a director of Bloggit tools Ltd. What happens is that "John Doe" waits for people to write cheques and if they leave out the Ltd he puts it into a personal "trade as" account. Usually the accounts are held at different banks so a bank doesn't get suspicious.
Anyway you could certainly start winding up proceedings on the dormant company and that might promote Companies House to do some further investigation - all of the directors will have their home addresses usually on companies house so you can write there, but as one friend says:
"Always write to the wives of directors - why, because wives probably know little of what their husbands are up to and they tend to get better results, and always feel obliged usually to reply.... "
A funny tip, but he said it worked...