I've built a small module to record details of SIM Cards issued to customers against subscriptions. I'm trying to extend this to have a 'SIM Cards' option in their account, but can't seem to get it to show up. I've created the following template loaded in manifest, but I must be missing something. Can anyone give me a pointer on what I'm missing?

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <template id="portal_my_home_er_simcards" name="SIM Cards" customize_show="True" inherit_id="portal.portal_my_home" priority="10">
	    <xpath expr="//div[hasclass('o_portal_docs')]" position="before">
            <t t-set="portal_client_category_enable" t-value="True"/>
        </xpath>
        <div id="portal_client_category" position="inside">
            <t t-call="portal.portal_docs_entry">
                <t t-set="icon" t-value="'/er_simcards/static/src/img/simcard.svg'"/>
                <t t-set="title">Your SIM Cards</t>
                <t t-set="url" t-value="'/my/er_simcards'"/>
                <t t-set="text">View SIM Card Subscriptions</t>
            </t>
        </div>
    </template>
</odoo>