Considering that you mentioned that "Shared Ownership Mortgages" is a new thing, I decided to go to Google trends and see its search volume over the years. What a dissapointment. No results.
So I went on to Google Adwords Keyword Suggestions and tried my luck there. That went better, moderate amount of searches in the UK.
Google trends does show results for "Shared Ownership" and some increase in the last 2 years.
an intitle:"Shared Ownership Mortgages" inanchor:"Shared Ownership Mortgages" intext:"Shared Ownership Mortgages" search in Google UK. Gives about 929 results. That's quite a lot. Youīre not the first.
Now I'm not sure what the above has to do with .gov sites.
But to continue the .gov discussion. Your second post already shows that .govs are more difficult to search engines than easy. Thatīs pretty logical because .gov sites don't have a comercial interest. When a citizen needs something from the government it won't be that difficult to find, as long as you know what their site is. In other words, there is no insentive for the government to be more search engine friendly.
But then how come .gov sites do rank just fine? Thatīs kind of obvious I think:
* lots of useful content
* no competition
* frequently updated
* lots of backlinks
* they talk about just about everything
* very trustable (don't disagree!

)
* etc.
Itīs like the ideal site for a search engine. They have no interest in high rankings..
What do you want for your website? Is the list above close to it?