The Camino Primitivo was quiet when we walked in April, but joining the Camino Frances at Melide the atmosphere changed as the numbers increased dramatically. Americans, Irish, Spanish, French, Italians, young and old, moved along- there was chatting in the evening and when meeting up along the road with people we had met before. The Confraternity of Saint James keeps monthly statistics via the pilgrim office in Santiago. In 2017 there were 301,006 pilgrims recorded, compared to 93,929 in 2005, with around 60% coming from the Camino Frances.
So many people as we move towards Santiago- a mixed blessing if quiet contemplation is preferred, but exciting as you are swept forward. Music, singing, groups of youths mainly interested in their mobile phone. This pilgrimage is nearing its goal with a sense of anticipation and also a sense of returning to the “real” world.
Was this atmosphere experienced in Bury St Edmunds? If there were enough people and things going on, then Yes! It is difficult to be certain of numbers, which varied with popularity and was probably declining even before the Reformation. There were fairs, including one for St James the Apostle in July https://www.history.ac.uk/cmh/gaz/suff.html which would have encouraged numbers.