Is it correct to say that if you flew in a level line from the top of Barr Beacon near Walsall (227m high) the next land you would "hit! would be the Ural Mountains in Russia
This may almost be true but needs some accurate research. Following a line 52.58N east from Barr Beacon, you just skirt some high ground just east of Berlin that would scupper it.
There is also ground of a similar height in eastern Poland and I think in places, this does go higher so it's possibly here that it would stop.
Even if it gets through this, it will definitely stop at the hills in the Orlovsk region of Russia (south of Moscow) well before it gets to the Urals.