OK - so the first step here is to invite the HP company to collect the caravan on the basis that you can no longer afford to maintain the repayments. You will need to check the termination provisions of the agreement, as depending upon the amount you have already paid off, the finance company may let you sell the vehicle in order the get a higher price. Once any residual debt due to the finance company has been established.
Once you have calculated exactly what you owe, then I would suggest you take professional advice from an insolvency practitioner as to your options. If you have some disposable income which you could offer to your creditors on an ongoing monthly basis, and IVA or Debt Management Programme are also alternatives.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk