I agree with eamonn123456. In addition, two houses selling beside each other always makes me wary. Potential buyers will ask why two houses are selling out - bad neighbours?? etc
.... wow what a coincidence! how did that happen - did you know when you bought your semi-d that the house next door was also going to be one! I'd have only bought a semi-d if the house next door was detached - but hey that's just me!