For the US crowd, silverside is the part of the round closest to sirloin, so it's a working cut and fairly lean.
In order to keep this juicy you'll need to bard it, in other words add fat. I'd do this by wrapping the whole thing up in streaky (US style) bacon and then sear it at high temperature to give it that crust before turning it down and continue the roasting at a lower temperature. So turn your oven up full-whack and let it get good and hot, then rub your roast with some salt, then into the oven for 20 minutes, then turn it down to 160 and roast it until it reaches 120F/50c. Remove and cover with foil, then let it rest for at least 30 minutes. If you don't let it rest it won't get tender at all.
In all honesty silverside isn't a cut I would roast, and I've tried. It just too lean and has too much connective tissue to be tender. It does make a good braise though, which is what I'd do with it.