The important thing to remember about grinders is that, other than the coffee itself and ignoring water for simplicity, the grinder is the thing that determines the quality of your final cup of coffee. There is a mostly linear increase in quality from good entry level grinders like the Svart through the mid-level Baratzas etc. to the excellent Wilfa Uniform which is about as much as I would spend on a grinder for non-espresso coffee.
A good grinder is never a bad thing and is always money well spend for someone who loves coffee. The thing that grinds my burrs coffee wise is £££ bean to cup machines which almost always look hideous, take up too much space and make make much worse coffee than an
£8 plastic funnel or the cafetiere you still have from when you were a student making industrial strength Lavazza to cure hangovers.
I also note he's buying from Monmouth which will be excellent, well roasted coffee. This will already put his coffee in the upper end of most home coffee (it's quite hard to make it wrong in a cafetiere) and makes as much grinder as budget will allow well worth it.