From The Anvil - Polished Brass 3" Heavy Duty Latch - 51741 Style_Thresholds to get anything through this

to get anything through this letter plate

Heritage Brass Thumbturn & Emergency Release Antique Brass finish - RR4049-AT

Heritage Brass Octave Reeded Bathroom set Polished Chrome finish - RR3730-PC

Spira Brass - Georgian Mortice Door Knob - Polished Chrome - SB2119PC

They are CE marked and classified as follows:

From The Anvil - Polished Brass 3" Heavy Duty Latch - 51741 Style_Thresholds to get anything through thisFrom The Anvil Polished Brass 3" Heavy Duty Latch 51741 Polished Brass Dimensions Tube Size: 78mm (L) x 23mm (H) x 15mm (T) Backset: 57mm Forend Size: 60mm (L) x 25mm (w) Strike plate: 65mm (L) x 40mm (W) A heavy duty tubular mortice latch with an extra strong spring for use with any of our knob sets or unsprung lever handles. We recommend using a 2. 5" or 3" latch with our lever handles, and a 3", 4", or 5" latch with our knob sets. Performance