The song is in Bb (well, almost--the recording is a little out of tune).
Sounds to me like the guitar is capoed at the 3rd fret and playing in C.

 G   F   C   G

 G            F
Lovely Rita meter maid
 C           G
Lovely Rita meter maid


  C          Bb    F     C                 G
Lovely Rita meter maid nothing can come between us
 Am                  D              G
When it gets dark I tow your heart away

  C              F         Bb                  Eb
Standing by a parking meter  when I caught a glimpse of Rita
  C                          G
Filling in a ticket in her little white book.
C              F              Bb             Eb
In a cap she looked much older, and the bag across her shoulder
 C                              G           C  Am  Dm  G
Made her look a little like a military man


  C          Bb    F    C                G
Lovely Rita meter maid may I enquire discreetly
 Am                   D                  G   F/G  Em/G  Dm  
When are you free to take some tea with me?

C/G   G
(Ah)       Rita!


piano solo
  C   Bb    F    C    G
 Am         D         G


  C                F             Bb                  Eb
Took her out and tried to win her, had a laugh, and over dinner
 C                               G
Told her I would really like to see her again
 C                F          Bb                  Eb
Got the bill and Rita paid it, took her home, I nearly made it,
  C                         G             C  Am  Dm  G 
Sitting on the sofa with a sister or two

      C           Bb    F     C                   G
Oh, lovely Rita, meter maid, where would I be without you?
 Am                 D                G
Give us a wink and make me think of you!

 G            F
Lovely Rita meter maid
 C            G
Lovely Rita meter maid
 G            F
Lovely Rita meter maid
 C            G
Lovely Rita meter maid