Just wanted to add Mrs Robinson...
What you've described is absolutley.. completely.. and utterly.. normal!
Over the years we've extended, redone, extended more, done other parts, extended again .. and again, slapped on outbuildings in the garden and then did a total refurb on two houses over 2001-2004...
I know exactly how you feel! and it's ultra frustrating when cowboys do the work and disappear.. happens all the time! fortunatley for us, only the plastering was done badly and we got a guy in who was from China, could only say hello and tea and sankyou but flippin heck he could plaster!
In some months and hopefully not years, you REALLY will make some tea, sit down to enjoy that and feel elated at everything having been done nicely.. I can still remember the moment we did that ! it really then feels like it's all been worth it !
However, the drawback is, its not the actual heavy duty work that cuases the most headache, it's all the arguing and bickering and fighting just before that special cuppa tea moment which is 'Decorating & Finishing' .. that's just the last test! be prepared for allsorts of arguments and hair pulling at that stage!! which colours, which finishes, which handles, taps, tiles, paint, which coving style which architrave style etc etc etc....
Good luck and take pics of everything when it's done!
Cheers! DtM! West London & Slough UK!