replacing pads and discs on p38

i need to change the front and rear pads and discs on my 2001 p38. the manual i have downloaded mentions a LR service tool used to push the pistons back into the calipers. does anyone know if this is really required or can it be done without the service tool?
Also, is there anything else to look out for? One rear disc seems to be getting hot and has a burning smell after a long journey. i suspect the caliper may be binding on the disk and i'm hoping that by working the pistons in and out a few times it will free it off. Does anyone have any experience on this?
thanks

Just squeeze the pistons back with a G clamp or grips, I've never used the special tool, didn't know there was one and I've worked in a dealer for 8 years!!

With regards to the binding brake, check to make sure the sliders are free, pistons don't normally sieze although they would if the rubber boot was split, Also its not uncommon for the pads to sieze in the caliper, if they have, make sure everything is cleaned up on refitting and that the new pads are not a tight fit when you put them in.

thanks for the advice clutchdust. i was hoping to get away with using a g-clamp though on some cars (my peugeot 306) you have to turn the pistons and push them in at the same time.
good advice about the pad binding. that sounds quite likely what has happened to mine - i will investigate this weekend.

think i'm going to get mintex discs and pads as a place on ebay has quite a good deal on a set. - anyone have experience of mintex kit?