George Derham born approx 1800-1

[Anthony way]

I have access to a lot of records and not a lot of time to put up every single detail for each individual entry I would be here for weeks
The names are only to help those place somebody's location or age them at a specific date to help or eliminate  a possible relation and not really for those who want birth death and marriages
you are correct with the drowning in 1790 however he did not drown in Brownsea road as this road did not exist in 1790 the modern name Brownsea did not exist until 1903 he was actually buried in Hunger hill burial ground Poole. skinners chapel did not have Its own burial ground hope this may help a bit I'm local to Christchurch Bournemouth and Poole, of 67 years,  and Dorset directly back to1602 best wishes to all 

[LizzieL]

The name Brownsea road was from report in the Sherborne Mercury dated 18 January 1790, it gave a brief report of the inquest which had been held four days earlier.  So it was obviously being used a long time before 1903.
If you have access to FindMyPast or the British Newspaper Archive, you can search for the publication. It is on page 3, about halfway down column 4.
You are correct about the actual burial, it was at Hunger Hill, but recorded at Skinner Street, so presumably the place of the funeral.
If your family goes back to 1602, would that be to Edward Derham of Bloxworth, your 9 x great grandfather?

added
burial record says Leg Lane Protestant Dissenters burying ground, presumably Findagrave is using a later name

[Anthony way]

Brownsea sea road may have existed elsewhere in Poole but the current Brownsea road is situated on Sandbanks which in 1790 was a uninhabited sand bar, except the odd tramp with no roads, on to or leading to the sand bar. the Canford estate records has no recorded name until it became Parkstone on sea I have not read the article but it is common for names to be given by locals before being adopted officially. I would have to query how Benjamin drowned on the brig Mary Anne on a road it is most likely he drowned at the entrance to the harbour as it was notoriously dangerous

[LizzieL]

Brownsea or Branksea road is a channel not an actual vehicle road. It is off the SE side of the island. You can find it on historical maps on NLS website