Not according to the 5th edition of the Real Ale Almanac which gathers recipe information directly from the breweries as well as numerous other British sources that report that Landlord is made from %100 Golden Promise malt. What's your source for your information?
The American clone recipes out there and clone kits available from Northern Brewer and other suppliers include a bit of crystal, but they do so for the color more than anything else. The darker color can be achieved without the crystal malt by boiling longer than the standard 60 mins that most US homebrewers use. Try boiling for 120 - 150 mins or longer without the crystal
Wheat is another common addition found in supposed Landlord "clone" recipes. The only reason that I can think of to include wheat is because us Americans like to have a head on our beers whereas that's apparently not very important to British brewers or consumers. Looking through the Real ale Almanac, is pretty rare to find a British brewer includes wheat of any kind in their bitter recipes. I'm not saying it's not done, but it is the exception rather than the rule.