When you put the name Brooke into Griffin’s Valuation and choose Fermanagh you get 973 results, not for the name Brooke but for tenants of Brooke.
I only looked at the first 100 and they were all in the Civil Parish of Aghavea, all tenants of Sir Victor A Brooke Bt.
The details won’t open on my iPad but the date will be the early 1850s.
It would at least give you an area to search, but you should check all the pages in case there are other Civil parishes, you can then check for Maguires in each parish. A Gentleman is likely to have property of high value which should reduce the numbers a lot.
https://www.askaboutireland.ie/griffith-valuation/