The "Dodo-Postcards" watermark is NOT on the actual card – it is an online watermark only.
Liverpool. The Mersey Tunnel. Photochrom. No 75600
Liverpool. The Mersey Tunnel. Photochrom
The Mersey Tunnel. Liverpool. Salmon. No 2124c
The Mersey Tunnel. Liverpool. Cameracolour. Salmon. No. 2124
G. 269. The Mersey Tunnel. Liverpool and Birkenhead. Under the River Mersey to be opened by His Majesty the King. Valentines. RP. Multi View
Liverpool. The Mersey Tunnel. J. Salmon. Cameracolour. 1971
Liverpool. The Mersey Tunnel. J. Salmon. 1966
Liverpool. Mersey Tunnel. Photochrom