Check the stiff vacuum pipe from the brake servo to the inlet manifold, it also has a non return valve half way. Look for splits at all the joints.
BZG is IMO a pretty decent engine, 3 pot HTP engines get a lot of unjustified criticism, but the real reason is because they were cheap bargain motors, a large number of owners are cheapskates or just plain ignorant and never look after them, service them on time or correctly. Oil changes are frequently ignored, incorrect oil used etc. A death sentence for any ICE
At least the BZG has a decent roller cam chain instead of the disastrous inverted tooth chain abomination of the EA111 tsi series.
I think only the most well serviced examples will see over 150,000 miles and 200,000 miles would be exceptional. Don't think I've heard of any HTP engine reaching that mileage.
Any engine or gearbox can of course be repaired/refurbished but most will get scrapped prematurely when major issues occur as either it is deemed uneconomical or the owner just wants a change or doesn't want to get involved or take a risk as there are many cowboy garages around ready to rob you blind with shoddy and overpriced work.
My 2009 fabia has a BZG engine on 102,000 miles. It is by far the easiest and cheapest Skoda in our fleet (currently fabia mk2, octavia mk2, superb mk3) to service and maintain.