By inspection, it seems that these NOTAM positions are DD:MM:SS values rather than DD:MM.
The UK AIP uses a mix of DD:MM:SS and DD:MM.m values.
Surely it is time to standardise on one system? Quite why a NOTAM needs to include values to the nearest second is beyond me - if DD:MM is good enough for FPLs, then why not for NOTAMs?
I e-mailed the CAA's Dawn Lindsay about this issue and have already had a helpful response. It seems that the problem has already been raised by others and is now being considered by the Head of Aeronautical Information Management.
Out of interest, do people prefer DD:MM:SS or DD:MM.m? In other words, do you prefer to enter waypoints as 503030N 0010042W or as 5030.5N 00100.7W?