Who Gets the Spot?
Answer: Your dilemma is perhaps based on a halachic opinion that one who is accustomed to having a particular mohel circumcise his sons should not take another mohel in his place, just as one who was accustomed to giving a particular kohen his tithes should not switch to another.
This is true, however, only in regard to something that is obligatory, such as giving a kohen the tithe or arranging for a mohel to do the brit on his son. There is no obligation, however, for someone to give permission to another to build a succah in his yard. This may be compared to one who is accustomed to lending his tallit to another. Does it make sense that he will be restrained from lending it to someone else instead?
In conclusion, you can definitely give that spot to your relative but try to pacify your other neighbor so that there will be no hard feelings.
- (Based on a ruling by Rabbi Yitzchok Zilberstein, rav of Ramat Elchanan in Bnei Brak)