Reports for the First World War submarines are available from Historic England’s website:

U8, the earliest German U-Boat casualty of the First World War, was lost off South Varne Buoy in the English Channel. 

The archaeological assessment included a marine geophysical survey, consisting of sidescan sonar and magnetometer, undertaken by an Autonomous Underwater Vehicle (AUV). The surveys revealed a relatively intact wreck, sitting upright on the seabed with the conning tower, up to three periscopes and the radio mast still in place. Assessment against non-statutory criteria for designation determined the wreck was highly to extremely valuable. 
Read the full report here.
Following the archaeological assessment, Historic England advised the Secretary of State for Culture, and the wreck was given protection as a Protected Historic Wreck site.

UB12, a type UB-I submarine, lost off Ramsgate 

An archaeological marine geophysical survey was conducted over the reported possible location of the UB12 wreck site off Ramsgate. The side scan sonar and magnetometer surveys revealed a very large magnetic anomaly, indicating the presence of a large amount of buried ferrous material, just 11 m south-west of the UKHO’s recorded position of UB12. In addition, 10 further geophysical anomalies of possible archaeological potential were identified in the area.  However, the work undertaken so far was not able to confirm whether the site represents a wreck site, and the size of the magnetic anomaly appears to be too small to correspond to the UB12. 
Read the full report here.

HMS D5, a British submarine lost off Lowestoft in 1914.

Wessex Archaeology conducted a two stage archaeological investigation at this site. The first stage comprised a geophysical survey over the location of the wreck site aimed to confirm the presence of the wreck and to inform the second stage, a diver investigation. The diving survey assessed the wreck on the seabed, and recorded the site using still photographs and video.
Read the full report here.