Can someone please tell me how to marshall the following?

enum
{
    LIFFE_SIZE_AUTOMARKETREF = 15
};

typedef char LiffeAutoMarketReference [LIFFE_SIZE_AUTOMARKETREF];

typedef struct _tagLiffeSettlementList
{
   struct _tagLiffeSettlementList* pcNext;
   
   LiffeAutoMarketReference achMarketRef;
   int nSettlementPrice;
} LiffeSettlementList;

Would this be correct?

[StructLayout(LayoutKind.Sequential)]
public class LiffeSettlementList
{       
   public LiffeSettlementList pcNext;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst=15)] public string achMarketRef;
   public int nSettlementPrice;
}

or would it be something like
[StructLayout(LayoutKind.Sequential)]
public class LiffeSettlementList
{       
   public IntPtr pcNext;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst=15)] public string achMarketRef;
   public int nSettlementPrice;
}

Thanks for the help,
Thomas