The Bell Tower, built in 1628, contains a peal of 5 bells, with the following inscriptions:
* Sancte Bartholemeo Ora Pro Nobis
* Sancta Katerina Ora Pro Nobis
* Sancta Anna Ora Pro Nobis
* Sancte Iohannes Baptiste Ora Pro Nobis
* Sancte Petre Ora Pro Nobis
The inscriptions follow a common formula for medieval bells, being all of the form Saint <name>, pray for us.
The trademark on the bells shows a bell hanging from a transverse beam, with the initials "T b." They were cast in Thomas Bullesdon's foundry in Aldgate. As Bullesdon died in 1510, these are believed to be be the oldest surviving peal in London. St. Lawrence in Ipswich also has a peal of five pre-Reformation bells, but they were made at foundries in Norwich and London, not by a single maker.
Photo from Webb Records vol. II, pg. 113.
St. Bartholomew's bell is the treble, weighing 5.5 cwt. Webb Records, v2 pg. 114 says:
"It is interesting to note that the treble bell is dedicated to the patron saint of the church. It is by no means the rule that medieval bells were thus dedicated, and more often the choice of a saint was determined by the dedication fo a chantry or altar in the church. Where the patron saint was honored, the tenor bell is usually the one chosen, but exceptions, as here, are by no means infrequent."
He cites Walters' "Church Bells of England" to support this statement.
In a posting to the ChurchCrawlers mailing list, David Bryant provided this additional information:
There are no complete pre-Reformation peals of more than five. There are a few fours (Thurlbear in Somerset and Torbryan in Devon spring to mind), and a larger number of threes - back three of four at Kittisford in Somerset springs to mind (Exeter foundry, I think) and the three at Hayton in East Yorkshire (York foundry), where I have memories of manhandling the badly-cracked treble out of the church and into a trailer to go to be welded.
You can hear Grandsire Doubles being rung on the St. Bartholomew's peal, on the Saydisc CD CD-SDL 378 Church Bells of England. Saydisc have graciously granted permission to provide a sample of the bells for download, so you can listen to them yourself.
Download 1-minute sample of Grandsire Doubles here (file size 1.6 MB)
Many thanks to David, as well as Alan Taylor (both of ChurchCrawlers) for correcting me and providing additional information about the art and history of bell ringing.