Ah. The plot thickens! I am like a dog with a burglar's arse on this one

Right then, some more investigation. Here we have GWR's 1935 map of the railway works:

The canal has nearly been filled in completely. The gates are just above the building marked as "Motor Shed". Si's picture was taken in March 1953 so this is twenty years before that. Note the line of trees above the carriage shop which are part of the "Recreation Ground".
Let's go back to 1899:

Here you can see that the canal is still intact, including the locks and the keeper's cottage further north. The GWR has not yet bought the land for the carriage shop. This is the original size of the recreation ground, note the line of trees. The footbridge over the canal leads to the exact location of gates which are at the corner of the recreation ground and the railway works. There is a footpath that leads across the rec at the same angle that the gates are to the canal. This strongly suggests that they existed before the works.
So perhaps they were originally the gates to something else? Well if we zoom out slightly:

There is a collection of buildings called South Brook at the top right. Was this the original instigator of the gates? Was it a farm or an estate perhaps? Did they subsequently sell off the land?
Let's go further back to the first Ordnance Survey map of 1828:

The railways have only just arrived here. No railway works, no Swindon New Town, just fields. South Brook is here, but there is no sign of a path or road where the gates are (the one further north is Iffley Road, leading to what is now Bruce Street Bridges).
I think that a map between the two (somewhere around 1860) would provide the final answer as to when the gates appeared and what they were for. However, I would dispute that the GWR made them and that they were in fact for the park and they were just incorporated into the new entrance for the carriage shop. If you look at the style of railing on the left and then compare it to the gate in this picture:

You can see that the gates are finished much more finely. The railings are typical railway style with curved tops and no embellishment. It also looks as though the railings have been attached to the gates with brackets. This is even more obvious in Si's picture:

I rest my case for now
