1. I think anyone is going to do "better" by having the lessons closer together. Now I know you said you can afford on average around three a month. If possible see if you can perhaps book a morning and afternoon slot one day and a third slot within a day or two of the first two,
2. Circuits get boring, and learning should be fun, particularly if you are taking your time. Tell your instructor you are getting bored and ask if you can cover some of the other aerial work away from the circuit even if this means your PPL takes a few hours longer. In fact you might find this helps you with your circuits,
3. Beg, borrow or steal some P2 trips with qualified club members - you will be amazed how much help flying with others can be in helping you get your own circuits together. Good landings derive from seeing the "right" approach perspective time after time. Ideally fly with another club member who rents or owns the same or a similiar aircraft to that in which you are training,
4. Book one lesson on a day you happen to know your instructor is away or booked with someone else. Just sometimes the chemistry between you and your instructor is wrong. You might find you get on better with a different instructor and make better progress. After all you have got nothing to lose.