Disco 2 New Boy - lots of questions!

Hi all. I'm new to the forum and new to Land Rovers. I'm hoping I've just bought a bit of a bargain in a Discovery 2 ES Premium. The garage thought the crank shaft oil seal had gone so I took it off his hands at a 50% reduction in the window price. I've subsequently discovered that the source of the leak is stripped threads on the sump plug! I've decided to replace the sump casing so I can replace the gasket and check the oil pump pulley bolt that I've read can be an issue on earlier models due to a lack of loctite on the threads. Would you guys recommend this course of action or look to remove the old plug and do a helicoil repair? I've a few more questions so any advice would be greatly received. Firstly, the ACE has been inhibited (pump removed and pulley installed) but the original anti roll bars are still fitted. Does this matter? Would replacing with standard ones reduce body roll? If so, what do folks recommend to replace them with? Secondly, the tailgate lower hinge pin looks to have significant wear in it as it clicks and moves about as the door is opened and closed. Is there a way to sort this? I've already sorted the drivers door with the split dowel replacement but think the tailgate maybe different? I can see a small circlip on the top so assume I need to remove this? The main door hinges appear to be fine with no wear/play in them. Lastly (for this post anyway!), can anyone recommend somewhere that does underbody wax oil treatment in the Leicester/Lincoln area and rough costs of what I should expect to pay? Sorry for the lengthy post!

Why am I having this feeling of Deja'vu?

I was advised to put my post in the Disco forum if you're referring to why you've seen this post before. So far I've had two replies, one useful and this one. If you've nothing valid to offer then why bother mate?!!

About the sump IMO better do as to check the pump bolt to be on the safe side, about ACE, you can improvise with what you have or install classic bars, to improve the existing setup there are two ways,you need to have tools and handiness but it's very cheap:
1. remove the banjo bolts from the two ACE actuators, cut a interior thread into the feed ports, find some grease nipples which you can screw in in there then fill the actuators with thin grease both sides(those actuators are like a syringe inside)...use a grease gun and fill the rod's side all the way with the other side open utill the rod goes entirely in then fit the nipple on the oposite side and fill leaving the grease out on the other side untill the rod comes out enough to have a straight bar, fit the grease nipple back and "pump" grease in both sides to refuse ...then it will act like on conventional anti roll bars.(like ACE in "locked bars" condition)...the gist is to have the actuator stuck if you see what i mean
2. fabricate a a T piece from steel bar which replicates the actuator or a bracket as to lock the actuator as in the attachment. if you get the point you can improvise many ways, important is that the section where the actuator is to become solid

Thanks mate, much more useful to me and very much appreciated. Lots for me to go on there. I'll be sorting the sump out first before I look at the anti roll bars. Do you think they're worth doing? Would there be a noticeable difference in the ride? I've predominantly bought the vehicle for towing a horsebox so it's more of a second vehicle/weekend use mainly. Thanks again!

Yes, diabled ACE in this mode like your's is similar wit the system failure named "floppy" , if you want a safe ride especially when cornering at higher speed put classic ARBs or bodge it as to lock the actuators

Looks like a bargain

ACE, depends on what is left, reinstatement with new (to you) pump and hydraulic hoses from a specialist*, or replace with non ACE bars, depends why it was removed.

Personally I like the system but would prefer standard to permanently locked

* Farm or HGV people?