Hi Linda
First let me congratulate you on choosing a VBAC.
I have never soon anyone having a local anaesthetic for haemorrhoids but I don’t think I have ever seen anyone with the problem as bad as yours sound. Theoretically there is no medical reason that I can think of to stop you from having a local in fact, I would suggest that it is a far safer option than another CS. As this is a somewhat unusual request you would need to discuss this with your OB and get him to order it. Another problem that I can think of is that the midwives may be unwilling to do this if they have never done or seen it done before. That can easily be overcome by the procedure being by your OB or the hospital doctor.
One way to help reduce the chance of this problem arising is not to be directed to push. Your body will tell you when it is time. Listen to your body not the midwives/ob.
I don’t think that pethidine is a good option. It is not a very effective method of pain management for this type of pain. It will only take the edge of the pain and it has a number of undesirable side effects.