The 32kg limit is common to all flights from UK airports. It's the maximum weight, under Health & Safety rules, which baggage handlers are allowed to lift.
Quote:
"Checked baggage in excess of the checked baggage allowance per passenger will be charged a
fee per kilo" (The bold type is mine)
Source:
http://www.ryanair.com/site/EN/faqs.php?sect=b ag&quest=excessbaggage
As I think you've already seen here,
http://www.ryanair.com/site/EN/faqs.php?sect=C HARGES ,
you can pre-pay for up to 3 items of baggage, at �3.50 per item, subject to a maximum weight of 15kg. Excess baggage has to paid for at the airport, where the charge is �7 per item plus �5.50 per excess kilo.
Chris