From Wikipedia:
"Royal Ordnance designed variants with 105 mm Royal Ordnance L7 gun as an upgrade package for owners of the Type 59. The upgrades incorporated 105 mm L7A3 gun with thermal sleeve and ammunition stowage of 34 rounds, British smoke grenade dischargers on both sides of the turret, Graviner fire-suppression system, Vickers Instruments L50 gunner's sight with laser-rangefinder, Avimo driver's sight night-vision device, Marconi's Centaur weapon system with digital FCS, Mantis commander's sight and solid-state drives. Another upgrade package also installed ROMOR-A reactive armour on the side hulls and ROMOR-B passive appliqué armour on the front hull and turret, along with the aforementioned upgrades. The Type 59 tanks used in the project were acquired from Pakistan, and the upgraded tanks were exhibited in British Army Equipment Exhibition 1984.[27][28] No Type 59s served with British forces."