A strong housing rental market showed through in specialist buy-to-let mortgage lender Paragon's latest figures with underlying quarterly profits of £18.1m and a pre-tax total of £18.7m.Arrears over the three months to December were 83 basis points (76bp excluding the acquired portfolio), continuing the downward trend in the percentage of the portfolio experiencing payment difficulty, Paragon said.In September, the lender agreed a new £200m warehouse loan facility. Utilising that, new mortgage advances totalled £8.8m over the past four months, with the pipeline standing at £75m.