There are two types of SIDs that are utilised in the UK, the old convential style of SID and the new RNAV style of SID
Conventional SIDs are the old style of SID where the departing aircraft navigates using “old” methods of navigation like VOR tracking that are not used as much nowadays as they have been replaced with newer forms of navigation like GPS.
This is an image of the BOGNA 1M and HARDY 5M departures out of Gatwick. The way to tell that this is a conventional SID is that there are VORs drawn on the chart, and there are references to radials and DMEs which are not referenced on RNAV SIDs. To make the chart easier to understand, there is also more of a verbal section at the bottom of the chart, better explaining the procedure to be followed on the departure. All aircraft are able to fly conventional SIDs as they all possess the ability to track radials and to tune into VORs and NDBs.
RNAV SIDs are a new style of SID that utilizes GPS as their primary form of navigation in the form of waypointds, predefined coordinates that are identified by 5 letters/numbers.
RNAV SIDs can be identified by a lack of VORs and NDBs being present on the chart, and the route section will state to fly between waypoints, not to fly radials. RNAV SIDs require less work than conventional SIDs as you are able to put the waypoints in the FMC and fly them rather than doing the difficult bits of tracking VORs, requiring tuning in for each of the VORs used and the different radials used, this means that the aircraft are more accurate on their departure (overflying very similar routes) and means that there it is less likely for mistakes to be made