I'm not mechanically experienced either and I was really scared buying my Zed a few months ago, it's the most expensive purchase I've ever made! I paid an AA dude to check it out for me and he gave me a long report which I got the garage to do some of the work before I collected. Looking back now this was an expensive choice but it saved me a few quid on the jobs they did and gave me peace of mind (which I was really pleased to have), it also gave me a list of the smaller jobs that needed doing, which I'm working through. However it comes with zero guarantees from the AA so if they miss something big, you're still on your own and it ain't cheap.
It might be a decent last resort but if you know a grease junkie they will probably help you, or, if you ask nicely on here and are lucky enough that there's an experienced Zedder near you, they might check it out with you. I was blown away by helpful and friendly everyone is here, still am.
Good luck.