I am the founding President of a group called the Gild of Clerks, a society for the study of medieval and medievalist liturgy. The Gild's principle focus has been 'liturgical archaeology' and it has worked on pioneering projects reconstructing medieval parochial liturgy. The first project the Gild undertook was a Requiem mass according to the Use of York, held in All Saints North Street in York in 2002. It was part of a Colloquium organised in conjunction with the Centre for Medieval Studies at York. It led to the publication in 2005 of a volume of essays Mass and Parish in Late Medieval York The Use of Yorkedited by Barnwell, Cross and Rycraft, to which Allan contributed. This first mass was followed in 2004 by a mass for Corpus Christi according to the Use of York, also in All Saints. A couple of video clips from this reconstruction can be seen below. Then in 2008 the Gild reconstructed a mass for the Assumption according to the Use of Sarum, held in St Peter Hungate in Norwich.
In all of these reconstructions I have been the lead researcher, compiling the texts and translations and transcribing plainsong from primary sources. You will the programmes of each of these events on Allan's Academia.edu page. The driving force of my work with the Gild has been a deep curiosity about the mechanics of worship, a desire to know how medieval church buildings functioned, but also some sense of the aesthetics of late medieval parochial liturgy.