When my rust bucket had the same problem, I adjusted the lens to the best I could get and secured it with a screw from the top, thru the metal. Again my rust bucket.

Dave
As far as I know all Aussie Volvo's have euro spec headlights..give thanks.. the US version has plastic front which goes cloudy over time, ours are nice thick glass. You would make some good money shipping 240 euro headlights over there, they seem to have problems getting them.
To your problem, The earths are (looking from front into engine bay) on the LH and RH fenders. The LH one is below the washer bottle, you will have to pull it out. the RH is on the bracket next to the battery there are 2 earths on the bracket mounting screws, one is turn sig and one headlight. There is another earth inside for the low beam relay on the floor near the shifter. I am not exactly sure on these but they are in the Bentley manual. (mine is at home) BTW low beam relay is in the dash somewhere.
Also sitting on this bracket next to battery is the high beam relay, you should hear it click, it is more likely you have a broken bulb if one side works on high beam, they both go through the same relay.
It is real easy to get the headlights out and appart, if the reflectors are dirty light intensity will be bad. I tried cleaning my reflectors (soap and water) but had little sucess, maybe brasso would help but be careful not to make them worse (try a corner). As for the pegs, mine are intact but look badly degraded. I would say replace these but I do not know if you can get the part or have to get a whole headlight. Try volvo for little post or try wrecker if you have to get whole headlight.
Good luck
Karl in Sydney.

re.: <> I'm familiar with the lights installed on U.S.-bound 240 cars and the mounting pegs are external - if broken, they'd fall off the car - not inside the light. Are these Euro-spec. lights?