Subject: Your [number]-room flat, [street or listing number]

Hello [Ms/Mr Name],

I'm interested in your flat in [street or area] and would like to view it.

[I would move in alone / My partner and I would move in / The three of us would move in, with one child]. I work as a [job] at [employer]. I could move in from [date].

I can come to a viewing [on weekdays after 5 pm / at any time that suits you].

Kind regards,
[Full name]
[Phone number]