Multipla Glowplugs

Sorry if this is a recurrent post (did google but couldn't see anything recent). A work colleague has a Multipla JTD 2003 issue and wants to change the glowplugs as Fiat want to charge £150 for the job. Are there any tips on doing this because apparently they're down the back of the engine somewhere (so he tells me)?

Thanks

Malc

Cost me £120 a few years ago on a Bravo TD100 as they were awkward to get at and some dismantling of other parts was required to allow access.

Andy