An explicit power-saving bound for Sárközy's Theorem on shifted primes, assuming GRH

Assume the Generalised Riemann Hypothesis. If $A\subseteq \{1,\mathrm{.}\mathrm{.}\mathrm{.},N\}$ contains no two elements differing by $p+1$, $p$ prime, then $\mathrm{\mid }A\mathrm{\mid }\ll N^{\frac{79}{80}+o(1)}$.