This 12" chartplotter covers UK, Irish sea, North sea, English channel, Bristol channel, 

Includes Shetlands, Orkneys, Hebrides, Scilly Isles, Isle of Man, Ireland coast, France coast, Spain coast.

I don't think you need to buy C-Map charts as these are very good.

AIS Class B built-in

Connect to your DSC radio or any other devices via NMEA.

Zoom in to 0.005 Nm

C-Map Max on SD card compatible.

1 year warranty

Unit is 24.2 cm x 15.2 cm, when bracket fitted width is 28.5

Items in package are the plotter, antenna with mount, plotter mounting bracket with screws, power and NMEA cables.

Display unit: Screen type 12" Colour TFT LCD screen with resolution 800 × 480 pixels (WVGA)

C-Map MAX SD Card support

Brightness 500cd/㎡

Language; ​​English

Standard chart screen; 

GPS data: 3D navigation; compass;

10,000 waypoints; 200 routes (100 points each); 

10,000 2 marker points; 200 boundary lines (40 points each); 1.5 million track points

Interface 2 channels NMEA0183 output, 1 channel AIS input data capability

Chart; Detailed XINUO chart (C-Map Max SD compatible)

Working Temperature -15℃~+55℃

Waterproof grade IPX5 which is standard for all Marine Chartplotters

Power supply DC 12V~36 V

GPS/WAAS

GPS receiving type 22 tracking/66 channel receiving, support WAAS/EGNOS/MSAS/GAGAN      

Receiving frequency L1 (1575.42MHz)

The first positioning time is less than 39 seconds (cold start)

Tracking rate 999 nautical miles/hour

Coordinate system WGS-84 (or other)

Precision        

          GPS positioning <15 meters (95%) out of range of WAAS beacons

                                      Speed: 0.1 nautical mile/hour RMS steady state

          DGPS (WAAS)  positioning: <3 m (95%) within range of WAAS beacons

                                      speed: 0.1 nautical mile/hour RMS steady state