There were 7 sets of Richardson twins born between 1884 and 1905 (not all to the same parents presumably!). You can identify twins as they have the same reference number on Freebmd. Two sets died within the same quarter shortly after birth, and others died individually aged 0 or 1. Some of the remaining babies may also have died, but can't be identified from the index because they have common first names. As you have birth dates for the surviving children, you may be able to hazard a guess at which twins may be yours. The only way to check for sure would be to order birth certs for one child from each set of twins or you could try crosschecking on IGI to see if they were christened and if the parents' names match.
Afterthought;
Also, if one twin was stillborn, it would still be a twin as far as the parents were concerned, but it would not have been registered, so you won't spot those twins in the birth registrations.