Given the estate's size and the 3 centuries over which it was mainly developed (17-19th) it is likely to contain a wide variety of styles. Certainly the ICOMOS documentation "majors" on the English Garden as it was seen in Europe - and the landscape has all the right influences to be so categorised. The words "French" or "Italian" are not, as far as I can see, applied as epithets to the gardens anywhere in the Evaluation - though the word "Baroque" is used a few times. Conversely there is a lot about the garden's English provenance.
It is quite fascinating to look at Web sites from various countries and see the differences in emphasis they place on different aspects!! Wiki in particular provides a direct comparison
Herwith Wiki on Lednice
a. English speaking -
"The surrounding park is laid out in an English garden style and contains a range of Romantic follies by Joseph Hardtmuth"
b. French speaking
"Comme le palais attenant, il subit maintes métamorphoses. Jardins Renaissance tout d'abord, parc d'inspiration baroque italienne dans les années 1730 avec terrasses et sculptures décoratives, puis dans le gout anglais au XIXe siècle sur les plans de l'architecte Fanti. La rivière Dyje est alors captée pour alimenter étangs et canaux enjambés par des ponts. La dernière transformation en date a lieu en 1884–1887 quand, sur les plans de l'architecte Michelli, dans le gout néo-baroque français à la mode, le parterre regagne les formes géometriques, les sculptures antiques, fontaines, buis taillés et boulingrins qui auraient pu être là deux siècles auparavant."
So, the latter emphasies the "Italian Baroque" and makes a passing mention of the "English style" before moving on to "French Neo-baroque"!
I also found this quote in another French Web site "Les Jardins de Lednice-Valtice est un domaine de plus de 156 ha composé d'un jardin à la française et d'un autre comportant de très nombreuses plantes originaires d'Amérique du Nord et de nombreux étangs. On peut aussi y voir un l'aqueduc romain ou des sculptures. Le nombre et la qualité des édifices éparpillés sur le domaine Liechtenstein sont une des raisons de son inscription au patrimoine mondial de l'Unesco. " ( http://www.a-tout-prague.com/fr/guide/la-moravie/lednice-valtice/
). So that is that then according to the French - the 156 ha is a French Garden with N American plants, scattered buildings etc etc and no English influence at all!!
Regarding Valtice - The French Wiki doesn't mention the gardens whereas the "English" wiki states "The palace is surrounded by an English park"!
The ICOMOS evaluation concludes "Among the designed landscapes in Europe the Lednice-Valtice example is pre-eminent for the way in which it combines very diversified cultural and natural Components, for the range and quality of those elements, and for its extent.....It succeeds in bringing together in harmony cultural monuments from successive periods and both indigenous and exotic natural elements to create an outstanding work of human creativity."
The reality must be that one could find, within the inscribed area, most aspects of fashionable garden design from the periods during which the gardens were constructed - ie English, French and Italian. However it seems to me that it represents, par excellence, an English Park (Garden) as seen by Continental Europeans - but I would say that wouldn't I -perhaps I am as biased (or culturally introverted) as those French Web sites!