Thanks to everyone for the replies so far.
According to the Manuel, ref. Page 97
Fuel filter change every 15,000 miles. I have over 30000 miles and no problem with my filter and sump plug,Why would the sump plug require changing if it’s not leaking?
On my cars previous Dealer services they have charged £5.95 plus VAT for a new sump plug each time. I assumed that it has an integral crushable washer and this was the reason for its replacement.