The fact that a company has gone into administration doesn't necessarily mean that it has ceased trading. (Several professional football teams, e.g. Leeds United and Ipswich Town, have gone into administration and later come out of it).
Your first step should be to find out whether the company has been dissolved or liquidated. To do this, go here:
http://wck2.companieshouse.gov.uk/31d3430d69a2aa3677c3db e1e3e62569//wcframe?name=accessCompanyInfo
Enter the company name and place check marks in 'Alpha Index' and 'Current / Recently Dissolved Names'. When the search results appear, look to see if 'Dissolved' or 'Liquidated' appears against the company name. If so, the chances are that you can wave goodbye to your investment.
If the company does not appear to have been dissolved or liquidated, click on the company name. This will show some very basic details about the company, including the current registered address and the date that the last set of accounts were prepared. If you click on 'Order information for this company', you'll be able to purchase a downloadable copy of the most recent company accounts. (Don't worry. It won't cost a fortune. The accounts, and any other documents available, only cost �1 per document).
Further to this, I suggest sending a letter, by recorded delivery, to the registered address of the company, asking for information about the company's current financial status. (The letter should be marked 'For the attention of the Managing Director or Administrator').
Hoping this helps,
Chris