Disco 2 Tow Bar Bolts

Towbar arrived this morning for the Disco. Was fun collecting it from the post office - glad I found a parking place nearby!

Had vague intentions of fitting it this afternoon but having felt the weight of it its going to have to wait til i get back from my week away next week so I can ask my father-in-law to help hold it in place while I bolt it up.

Other minor issue is it didnt come with the bolts. Its all fully assembled so I think I only need 4 bolts. Does anyone know the sizes of bolts that I require? I'm assuming I also need nuts and washers for where the arms bolt onto the chassis. I'm told the holes in the rear crossmember should be threaded but they don't appear to be?

I'm working from RAVE: The bolts for the two fittings to the chassis mounts are M16 x 125, nuts and washers required. The bolts to fit to the rear cross member are M14 x 85. By the look of the pictures on RAVE, the holes are threaded.
Once everything is in place, the bolts should be tightened to 240 Nm for the chassis fittings and 140 Nm for the cross member bolts.
If you don't already have RAVE you can download it from:

http://landroverforums.com/forum/general-tech-help-8/link-rave-iso-images-42972/

This was discussed in a recent thread. They need to be high tensile bolts and the best way to get exactly the right ones is to get them from a towbar supplier.

The bolts in question are the ones which will attach the whole towbar assembly to the chassis, not the bolts which fix the hitch to the assembly which as you rightly say should be high tensile steel.
The bolts whch are used to fix the whole assembly to the chassis aren't under tension in normal service (other than the initial installation torque tension) but they are subjected shear forces. Yes, high tensile steel bolts could be used, but they're not absolutely necessary for the particular job they're doing.
Since the fitting of a towbar is a Land Rover accessory, I would suggest that you search for these bolts from LR parts suppliers.

Really struggling to find these anywhere online - any ideas? Possibly just being stupid!

Pack of M14x85 listed as "Land Rover Chassis Bolts" : http://www.ebay.co.uk/itm/land-rove...574249?hash=item33bd23d529:g:cGgAAOSwyQtVwMXJ
Don't know about the M16x125 bolts, check with Rimmer, Paddocks, Craddocks, Bearmach, even ScrewFix. There are a number of suppliers of Land Rover parts online.
The comments about high tensile steel bolts refer to the bolts which hold the towball to the towbar, they're M16. Also use HTS bolts for fitting the drop plate.
Anywhere where the forces in normal use tend to pull along the length of the bolt use HTS. Where the forces are across the bolts, "normal" steel will suffice but if HTS is available then use that.