Found this company on the net when looking for diesel glow plugs for my 1.9 T4. Very friendly service and very good value.
Four NGK (Individually boxed made in Japan NGK) Y918J glow plugs for £21.96p delivered. That's £17.20p for the plugs, a very modest £1.49 p&p(first class post) and plus VAT at £3.27p.
Nice to deal with a company that doesn't try to rip you off.