We have been down this route before, I wouldn't waste your time with liquidators, you may get 5p in the pound if you are lucky.
We had it with Etam, I had supplied them with good cleaning staff for years, they then slowed up with the payments, which flagged up in my mind.
I then read that they were in trouble in the Times, and immediately registered a non payment of invoice plea with our local county court, after months of ignored letters and telephone calls, surprise, surprise, the financial director called.
'Don't you know who I am' attitude at the beginning, and then, please hold of until 21st, I promise that you will get your money :

I don't think so, I still proceeded, on the 14th I received the full amount, which was about £5k, about a month later a ream of paper came through from a liquidation company naming hundreds of unsecured creditors, they went into liquidation on...... you guessed it 21st of the previous month.
These people are numptys, they couldn't care less about you and I, I think the secret is to keep on top of your invoices. Its happened to us many times over the years, if I smell a rat, then I am straight up to c-court.
Good luck
S