I asked the question about whether or not a Mewlon 300 would be suitable.
I got this very pertinent response:
Hi Greg,
I visited Sydney Observatory in October last year with the group of Urania (Antwerp/Hove, Belgium). I own a Mewlon 300 that I acquired used some years ago. This is a splendid telescope with excellent optics and good mechanical construction, this is valid for the other Mewlon diameters as well. The 300 needs a good mount and preferably a permanent mounting (26 kg, OTA only). It reaches thermal equilibrium quite fast (you can remove the back end covers for increased ventilation, but I would not recommend that when you have visitors using the telescope as the main mirror is exposed partially when you remove the side covers). As all telescopes it will suffer from local seeing and the more so since it has a 300 mm aperture, it will suffer more than a 6 inch APO but it gathers more light as well. I don’t think you could afford a 300 or 250 mm APO if this exist at all, but a Mewlon comes very near that I think with much less expensive glass and a manageable length. See my website http://www.astronomie.be/Tranquility.Base/ . The Mewlon 250 would also be a good choice, lighter and less expensive than the 300!
Best regards,
Geert Vandenbulcke
Also if you are interested in a historical type telescope there is one at Windsor - Tebutts Observatory. I don't know if they are willing or not but its worth an ask. Its a big ole refractor that's brass and stuff and looks the part.
Greg.