Suitable Replacement for a Dual Coil Latching Relay
Your part is made by Carlo Gavazzi and is

 M15=range
 |  M=3.5mm pitch
 |  | R2=2 coils
 |  | | I=reverse coil polarity
 |  | | | A=Ag CdO
 |  | | | | H=sealed
 |  | | | | | 001=SPDT
 |  | | | | | |   8=contact current in amps
 |  | | | | | |   | 3VDC=coil voltage
 |  | | | | | |   |
 M15M-R2I A H 001 8 3VDC



Datasheet at an Italian supplier Cimee https://www.cimee.it/gavazzi/23M15MR1IAH0018eng.pdf which might be able to help you.

It appears that the part is discontinued, and that perhaps this was a Feme part, a company bought by Gavazzi in 1988.



Possible replacements

I haven't seen anything which is electrically equivalent and also mechanically with the same pinout.

Searching on Digikey for dual-coil latching with 3V coils gave four with adequate current and contacts:


Perhaps you can find one which is small enough, mount it sideways with glue and solder some flying leads to the PCB holes?



Possible Panasonic Part

For example, perhaps Panasonic 

 Range
 |   Contacts: 1 Form A (NO) 1 Form B (NC)
 |   | Latching dual coil
 |   | |  3 VDC coil
 |   | |  | Reverse or not
 |   | |  | |  Contact material
 |   | |  | |  |
 DSP-1-L2-3-??-Any


I confess I'm not clear what the "Reverse Polarity" means on this part or your orginal one.


From Panasonic Datasheet



Possible TE Part

RT314F03

Or this pinout from TE looks close enough you might be able to make a few extra holes and solder the leads bent over.


From TE Datasheet