Empire Aluminium and Glass Solutions

So Empire Bifolding Doors & Empire UPVC Windows and Doors can apparently claim they are new companies, seemingly spawned from Empire Aluminium & Glass Ltd and appear to operate under The Empire Group UK Ltd banner.
The owners and directors of these companies were all involved in the window and door installation work at my home, albeit under the original banner of Empire Aluminium & Glass Ltd. This company left me with assembly and installation damaged, poorly installed, dirty, draughty, unfit for purpose uPVC windows (now apparently under the banner of Empire UPVC), and aluminium bi-​folding and French doors (now apparently under the banner of Empire Bifolding Doors).
While the basic products, before this company worked on them, seem to be of good quality, both our aluminium bifold and French doors were damaged during careless and incompetent assembly and installation. They both allow extensive cold air draughts to pass under the bottom brush seal, which the company has acknowledged but refuses to rectify, even under warranty. The opening windows on either side of the French doors also allow the free passage of outside air and have, like the uPVC windows installed by this company, had to be lined with sticky window sealing strip, which the company supplied free, but I had to install myself! And that is their solution to fixing draughts…
The uPVC windows installed during the same works are also draughty around the opening sashes and have had to be sealed with sticky window strip to stop them letting the outside cold air in. The triple glazed units on the large window were installed with dirty marks and hand/​thumb prints on the inside glazing panel. Although the company has tried to rectify this, by replacing the large triple glazed units on at least five separate occasions, we are still left with dirty marks and paw prints on the inside panel. The company now refuses to attend and rectify any further such faults. The units are also extremely poorly finished on the outside, with the white mastic fill around the periphery of the windows looking like it has been applied by a 3 year old. We believe these uPVC units, manufactured and installed by this company to be unfit for purpose.
They have also recently flatly refused to rectify warranty damage, which has further exacerbated the cold draught issue under the bifold doors. One of the above companies even tried to charge me £200 +VAT — just to come and inspect the problem, with no guarantee of a fix and additional charges if further visits were required?
In my opinion all of these, so-​called, Empire Group UK Ltd companies are definitely ones to steer well clear of and avoid like the plague.
Their customer service, in my experience, is unprofessional and non-​existent to the point of being discourteous and rude.
The products they install are, in my opinion, ruined and rendered unfit for purpose by careless and incompetent assembly and installation. In my view the workforce do not seem to have the appropriate experience and training, or even tools, to carry out any aspect of their work professionally or satisfactorily.
Think very hard before considering where you are going to spend a significant amount of your hard earned money people!