Well a poncho was required after all!!
Had a fantastic time in Green Bay and did the bars on Saturday night and went to a few tailgates on Sunday rather than paying and staying in one place - also joined a couple of groups tailgating on way to Lambeau (thanks for the hospitality / beer / burger).
Also went to the hall of fame on Saturday but didn't do the tour due to timing issues*. Spent a fair bit on merchandise but what the hell, can't easily get Packer gear in the UK (Xmas jumper has gone down well).
*Only issue I had was getting to Green Bay as my flight was delayed from the UK meaning I missed the connection. American Airlines couldn't get me on a flight until 28 hours later and even that wasn't guaranteed due to over booking. Anyway spent a night in Chicago and got a Greyhound bus to Green Bay first in the morning. Luckily I contacted the hotel who kept my room and didn't even charge me for the night I missed - thanks Econo Lodge, great service.
To anyone thinking of travelling to Lambeau go for it, in all I think I could have done the trip for under £1k if required. The people are great in Green Bay (and to be fair they were OK in Chicago too) and make you feel welcome. Experience of a lifetime in Lambeau - and we beat the Cowboys.
Thanks to all for the advice on this forum - really helpful.
Go Pack Go