I think possibly the MOT and Insurance requirements in Sierra Leone are a little less stringent than the UK……..
Personally in my opinion I would use a smaller wheel and higher profile tyre. I believe I am right in saying the most basic French version of the Vel used 16" wheels as per the Laguna. I expect they might be available locally, and could be fitted with a decently high profile tyre, maybe a 65 aspect ratio? You will need to check your wheel bolt sizes – early cars had 12mm wheel bolts, which fairly quickly went up to 14mm, but I don't know about Laguna or Espace wheels – I imagine they may have changed as well, but I don't know for sure.
Of course this solution would give a considerably narrower tread, which may, or may not be an advantage depending on what sort of road surface you are driving on.
From a quick look it appears 245 tyres are available in a higher aspect ratio (or 235) but they appear to be designed for 4 x 4 vehicles, or as winter tyres, which is probably not what you want!