The Millenco Mantis Mechanism is one of the more expensive lock mechanisms to replace and this will definitely be reflected in the final price you pay.  The Millenco Mantis MK1 is the only mechanism that has the unique 117/86PZ measurements that match the door handle. It may be possible to repair these locks but that is at the locksmiths discretion, as sometimes other parts of the lock may fail afterwards.  Many locksmiths feel it's best to supply a new system so they can provide a 12 month warranty.

The ERA Vectis is a 5 lever lock multipoint locks which was regularly installed in UPVC doors around 15 - 20 years ago.  The Era - Vectis 5 lever - Multipoint lock gearbox comes in two backset sizes; 35mm (Standard UPVC) and 45mm (Composite, Timber). The Vectis is also available in either a hook bolt or deadbolt model, which both have their pros and cons. If your ERA lock fails, there are two options for the locksmith.   1 - Replace the Gearbox or full strip with a like for like job.  This will often be the cheaper job as there are less parts and work involved. 2 - The locksmith may  upgrade the lock to a new style lock.  This will include new handles and a new Euro Cylinder.  There are more parts involved and more labour however many see this as a better job in many peoples opinions.  The price quoted on whatsthedamage.net includes a full refurbishment which means you get new handles and new cylinder keys.  This is the average price and does not include emergency callout or gain entry fees.