Rear springs

Hi i have tried seaching but to no avail
Is there a how to guide for changing rear springs on a 300tdi mine are a wee bit saggy what springs should i buy i have 235 /85/16 tyres i want to be able to tow and carry loads should i buy heavy duty or +2hd ?
I have a haynes book but it wants me to compress the springs can they be removed without comressors
Cheers
David

yes easily remove shocker at one end ,support vehicle under chassis put vehicle bottle jack between axle and chassis jack axle down till able to remove ,

not wishin to disagree but could that not snap ya rear flexi brake pipe?

if i jack mine up under chassis the flexi is near at breaking point...

its fine it will not break. its looks like it will but it wont.

on a 300 one side at a time ,on a disco 2 unclip sensor wire and theres enough room without going to far on flexi, ive never had problem with flexi ,