St. Aldate's Mystery Cache

A walk down the historical Oxford street of St Aldate's.

The hunt is designed so that you can gather all the necessary information walking along the east side of the street. It is generally but not all to be found in the order needed. 

This is a puzzle not a multi, as you will need your smartphone or another internet / research source to obtain some numbers, ie the authors of the 2 inscriptions. For all other info look in the street not online.

Starting on the SE corner of the crossroads known as Carfax, keep your eyes peeled!

All clues about years, ignore any months or days you may come across and just use the whole years.

A = first and last digits of the answer if you subtract the number of UK Prime Ministers who studied at Christ Church according to info found on this street from the year of a royal wedding also noted somewhere along the street.

B = years after the street name change indicated on a plaque, that the author of an inscription about studies was born.

C = years from when the author in B died, to the date immediately above the dancing lion and unicorn (an eagle-eyed finder has spotted another lion and unicorn far below a date further down the street, 53 years younger - not that one!).

D = years from CCC School being founded, to the Broad Walk being laid out.

E = years from New Walk being laid out, to a (minor?) Motor Man being born.

F = Exeter, if Worcester = 44 and Lincoln = 17.

G = years from the founding of St. Frideswide's Priory [specific reference to St Frideswide, not a "c.X00"; if in doubt you can Google this one], to the birth of the author of an inscription about his sword and what he intended to do with it.

H = years from Motor Man dying, to start of filming of a much-loved Endeavour.

J = number of minutes in a short trip if you don't want the all day cruise.

The cache is now a short walk away at N51º 44. (G + C + A - H) W001º 15. (B + D + J + F - E)

Please use stealth at GZ. You are looking for a black tube about 2cm diameter and 12cm long.