A floating charge on the undertaking or property of the company created before 23 June 1993 and within 6 months before the relation-back day is, unless it is proved that the company immediately after the creation of the charge was solvent, invalid except to the amount of any money paid to the company at the time of or subsequently to the creation of and in consideration for the charge together with interest on that amount at the rate of 8% per annum or at such other rate as is prescribed.