The issue of EICRs during a house sale is a thorny one. I've recently had cause to go and look at an installation that the seller's EICR claimed was safe and satisfactory.
The EICR was used to mask an un-notified board change (to install RCDs because the original surveyor commented on the lack of RCD protection). The quality of the work was horrendous but because the EICR said satisfactory they proceeded with the purchase. It wasn't until a family member (my AM2 assessor) went to carry out some works that this came to light, he then asked me to go and take a look.
My advice to sellers is that unless you have genuine concerns about the safety of the installation, don't do anything. Let the buyers shoulder the cost, but keep in mind that the buyers spark may be under instruction to 'get us a reason for dropping the price'. They may also be the kind of spark who finds things wrong to generate work.
If the buyers report comes back as unsatisfactory, it might be worth having a spark you trust (recommendation from family, friends, have previously used etc.) spend an hour with the report and the installation to double check the report. I was quickly able to establish the EICR from the seller wasn't worth the paper it was printed on and that's given the buyers some ammunition in trying to recover the cost of having the place rewired which is what it really needs (whether that will succeed or not is another matter but two electricians have visited the property on their behalf and found it to be sadly lacking and not at all as described on the EICR).
It's also worth pointing out that an EICR can have observations on it and still be satisfactory. Observations are classified as C1 (Danger present), C2 (Potential danger - i.e. something has to happen for the issue to become dangerous), C3 (Improvement recommended) and FI (Further investigation). Any C1, C2 and FI observations will result in an unsatisfactory EICR. So if the report has C3's only, this is no reason to drop the price as the EICR should be satisfactory (i.e. safe for continued use).