The Mann filter was a good choice by the shop, same as OE. I'd recommend buying the Mann filter on Amazon for when you do the changes yourself. I *think* (you can confirm) the part number is W94025 . If you were ever buying a bunch of stuff, E Euro Parts has cheapest price on the filter, otherwise Amazon is good if you qualify for free ship there.
The Pentosin is a fine oil too. I'm guessing you may go a shortish OCI on it though, trying to clean out some stuff. Sounds like she went to a competent Euro shop. Pentosin is pretty expensive oil, so the $120 doesn't surprise me.
Your cheapest oil to get that will do a solid job cleaning and fully approved is Mobil 1 0w-40. I don't know if you go to that infamous place that starts with a W, but it's only about $25-$26 for 5 quart jug there. Considering you want to do shortish changes to clean it out, I'd want to buy it at a good price like that.
Good luck.