Shop around. An ARF is a financial product and like almost any financial product, there's a wide variety of charging structures available. As a general rule, good brokers tend to be more competitive for ARFs than banks or tied agents. Again, as a general rule, you should be getting 100% investment (no up-front charge) and an annual charge well below 1%.
Whether or not this is an advisable course of action for you would require a full look at your overall financial position, that of your spouse etc.