Am planning an oil change on the TD6, i assume its best to replace the plug and washer on each oil change? And if so, does anyone have a part number for the plug & washer for a 2003 TD6 please?

No need to change the plug unless it is damaged

Thanks 47p2, so just change the washer?

What about the magnetic drian plugs,are they any good?

Magnetic drain plugs are great on a mini, but then they're also doing the gearbox too.

I would have thought if an engine alone is generating substantial amounts of magnetic material in the oil a drain plug is the least of your worries.