OK peeps need your help here on 2 burning merc issues for me & my dad!

1. Need to get genuine Merc E Class 320 car mats esp drivers without getting ripped off by buying from Merc direct.

2. Ongoing saga which needs a bit of explaination.
Bought my dad his motor E320 1998 S reg passed full AA inspection flying colour drove like a dream. 94K on the clock. Took it to Merc for service as has full merc service hx up to now and that crippled me but flew threw that with just an anti freeze top up required.

Then Merc told me about their TEIR 2 warranty! Said I could jump on board before the cars done 100K miles and would be covered including breakdown. Needed an appraisal first. Paid for appraisal car flew threw that no problems then . . . only after this has the car been no end of grief for some reason the car came back with the plastic covering around the steering column was loose. I sent it back to be sorted Merc agreed to repair FOC whilst refusing to accept blame. Then after this I now find my steering is not so sharp. . . . . . .

Has anyone had similar problems with Merc?
What are peoples views on the Tier 2 Warranty cover is it worth the money you pay just over 700 GBP?
Are there any reliable Official Merc garages in the London Area one could recommend? The one I used cannot possibly be a true and accurate representation of Mercs quality and class.