There is no Church of St Swithin, in Winchester,
The Church of St Swithun, is the parish church of Winchester, but…
<<The first mention of the church is recorded in 1264, when it was apparently burned by the citizens of Winchester during a dispute with the Priory>>
Therefore it may be wrong location for a burial in 1135.
However …it is more likely to be..
<<Winchester Cathedral is a Church of England cathedral in Winchester, Hampshire, England. It is one of the largest cathedrals in England, with the longest nave and greatest overall length of any Gothic cathedral in Europe. Dedicated to the Holy Trinity, Saint Peter, Saint Paul, and Saint Swithun,>>