He did have a practice in New Church Rd Hove.when I last visited him. I just googled John Byrnre Podiatrist and it showed as Richmond Podiatry Clinic Worthing with a tel no. I would start there.
Due to having diabetes I get to go to the podiatrist at Haywards Heath Health centre every 3 months under the NHS. It feels great when I leave and for a couple of weeks after. If it gets bad I would willingly pay for a visit between each NHS appointment.