Client side validation for custom validator asp.net MVC 4

I have a custom server side validator that works but I am struggling to get the client side working. Here is what I have so far.

The Validator is checking that one value entered is at least a percentage of another value entered.

public sealed class PercentageOfAttribute : ValidationAttribute, IClientValidatable
{
    private readonly string sourcePropertyName;
    private readonly int minimumPercentage;

    public PercentageOfAttribute(string sourcePropertyName, int minimumPercentage)
    {
        this.sourcePropertyName = sourcePropertyName;
        this.minimumPercentage = minimumPercentage;
    }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var propertyName = validationContext.ObjectType.GetProperty(this.sourcePropertyName);
        if (propertyName == null)
            return new ValidationResult(String.Format("Uknown property {0}", this.sourcePropertyName));

        int propertyValue = (int)propertyName.GetValue(validationContext.ObjectInstance, null);

        var minValue = (propertyValue / 100) * this.minimumPercentage;
        if ((int)value > minValue)
            return ValidationResult.Success;

        return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));

    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        var rule = new ModelClientValidationRule
        {
            ErrorMessage = this.ErrorMessageString,
            ValidationType = "percentageof"
        };
        rule.ValidationParameters["propertyname"] = this.sourcePropertyName;
        rule.ValidationParameters["minimumpercentage"] = this.minimumPercentage;
        yield return rule;
    }
}

And the javascript for the client side...

jQuery.validator.addMethod("percentageof", function (value, element, params) {
    var propertyname = params['propertyname'];
    var minimumpercentage = param['minimumpercentage'];
    var propValue = $('#' + propertyname).val();
    var minValue = (propValue / 100) * minimumpercentage;
    if (value >= minValue) {
        return true;
    }
    return false;
});
jQuery.validator.unobtrusive.adapters.add("percentageof", ["propertyname", "minimumpercentage"], function (options) {
    options.rules['propertyname'] = options.params.propertyname;
    options.rules['minimumpercentage'] = options.params.minimumpercentage;
    options.message['percentageof'] = options.message;
});

I have debugged the addapters.add function and this is passing in the correct data. The "data-val-percentageof-*" values appear in the html and have the correct values.

The javascript error I am currently getting is "$.validator.methods[method] is undefined". I think this means that I have not correctly set up the client side validator. I've read through countless examples and tutorials but can't seem to figure out a combination that works.

If I remove all my custom stuff then the default client side validation works perfectly.

Can any one help show me what I am doing wrong?

EDIT:

The rendered html is as follows

<div class="form-group">
<label class="col-sm-3 control-label" for="PurchasePrice">Purchase Price (£36,000 minimum) *</label>
<div class="col-sm-6">
    <input id="PurchasePrice" class="form-control valid" type="text" value="0" name="PurchasePrice" data-val-required="Please enter a Purchase Price" data-val-range-min="36000" data-val-range-max="2147483647" data-val-range="Please enter at least £36,000" data-val-number="The field Purchase Price (£36,000 minimum) * must be a number." data-val="true">
    <span class="field-validation-valid" data-valmsg-replace="true" data-valmsg-for="PurchasePrice"></span>
</div>
</div>
<div class="form-group">
<label class="col-sm-3 control-label" for="Deposit">Available Deposit (30% minimum)*</label>
<div class="col-sm-6">
    <input id="Deposit" class="form-control" type="text" value="0" name="Deposit" data-val-required="Please enter an Available Deposit" data-val-percentageof-propertyname="PurchasePrice" data-val-percentageof-minimumpercentage="30" data-val-percentageof="Please enter value that is at least 30% of the purchase price" data-val-number="The field Available Deposit (30% minimum)* must be a number." data-val="true">
    <span class="field-validation-valid" data-valmsg-replace="true" data-valmsg-for="Deposit"></span>
</div>
</div>