Very well-balanced British Shorthair, accustomed to indoor life

Our British Shorthair, Oliver, has been part of our family for about three years and has always shown an extremely balanced temperament. Unlike other young cats that run around everywhere, Oliver prefers to calmly observe his surroundings. He often spends the afternoon sitting near the window watching the birds or simply resting on the floor near the sofa. When visitors arrive, he first observes from a distance and then slowly approaches to sit near them. He is a cat who enjoys company but is neither clingy nor noisy. The reason we are looking for a new family is that a member of the household recently developed a severe allergy, and after several attempts to adapt, the veterinarian recommended finding him a new home. We want someone who appreciates the calm nature of this breed.