My toilets not a Twyford but most close couplingtoilets have 2 butterfly nuts that tighten the units together. Have a look underneath the toilet cistern where it joins the toilet itself, on either side ther should be a bolt attached with whats called a butterfly or winged nut, tighten both the wing nuts as much as you can and that should do the trick.
popeye1948, September 2009