Set defaults for distance and units, remove from url

Is it possible to remove from the search url the distance and unit parameters, to simplify the resulting url from proximity search?

Instead of a url looking like this:
field_geofield_distance%5Bdistance%5D=100&field_geofield_distance%5Bunit%5D=3959
.../?locn%5Bdistance%5D=10&locn%5Bunit%5D=3959&locn%5Borigin%5D=exeter

I'd like it to look like this:
.../?locn%5Borigin%5D=exeter

or even better:
../origin=exeter

because my distance and units will always be 10 and miles.

(I have used 'locn' instead of 'field_geofield' in an attempt to simplify the url.)

It seems sensible to be able to specify that in the View, but I can't see how it could be done.

Any pointers would be most welcome.