This last section is devoted to the proof of the asymptotic result as ε↘0 contained in Theorem 2.4.
Throughout the section, (xε,yε,ξε,ξΓ,ε) and (x,y,ξ,ξΓ) are the unique solutions
to (2.1) with additive noise B in the cases ε>0 and ε=0, respectively…