Hi Jane,
I'd echo what you say about the transcribers being unsung heroes. I don't know what I would do without such resources as the IGI.
Not sure on how to get a clearer picture of damaged pages, but for the 1600's, if the Bishops Transcripts survive for your county, then you could cross reference your information. The following relates to Devon records but will be applicable to England as a whole:
Bishops Transcripts
Introduction
These are contemporary copies of the Parish Registers - that is, copies made in the parish in the same year as the original parish register entries. Under an Order made in 1598 it was stipulated that within one month of Easter each year, the churchwardens were to send to the Diocesan Registry (that is, to the Bishop) a copy of all the register entries for the preceding year. Note that these copies may not be an exact copy of a register entry. Some transcripts were made first, and copied up into the register before being sent to the bishop, and some do not contain all the information found in the register, while some contain more.
Bishops transcripts are useful to the family historian in cases where a parish register is missing, or where there are gaps or difficulties in reading existing ones. These transcripts are now stored in the Diocesan Record Office. This is usually, but not always, the County Record Office. If a diocese includes more than one county, the transcripts for that diocese may be split by archdeaconry, and stored in the relevant County Record Office, instead of together as a complete group with all the other diocesan records.
Early Bishops Transcripts (up to 1812)
Bishops transcripts are available for almost all Devon and most Cornwall parishes. The earliest transcripts date from 1598, but because they were written on paper, very few survive from the early 17th century.
No transcripts were written during the Commonwealth period because there were no bishops, and many of the Anglican clergy were deprived of their livings. The keeping of bishops transcripts was recommenced at the Restoration and most parishes have a reasonably good series from 1660, and this is especially so for the second half of the 18th century.
From
http://www.devon.gov.uk/index/community/the_county/record_office/family_history_3/bishops_transcripts.htmSasha.