Nice report mate. Travelling around Eastern is always a bit unlucky. Good that you decided to look around instead of heading for Auschwitz only (come on guys...it's like going to the UK to see the Big Ben). Pity the skull chapel was closed - it's pretty impressive.
For those who are planning to go there I would recommend to avoid centre of the country as it is nothing special. If you come from the north you can go along the coast (widest beaches in Europe), visit Gdansk, party in Sopot and head east for a lake district called Mazury. It is a great region with over 100 lakes often connected by channels or rivers. Very laid back atmosphere there so make sure you have enough time to enjoy and don't plan to leave very early in the morning - yes you will meet people and yes you will be forced to have a drink (though I should probably emphasize plural form).
Then you can go down to Warsaw, big concrete town but hey it's a capital. Hotels like Kyriad or Campanile are in the center and can be had for £35. From there you can go to Krakow, enough said about this great city. I can only add they have by far the best hostels in Europe according to Guardian and the nightlife is epic. Then head south to Tatra mountains. For the vibe I would suggest Zakopane. You can find accommodation from private people waiting next to the main bus station. If they speak some English you should be fine. Make sure your accommodation is in a detached house (villa) and not in a block. You can always see the place before paying for it. You can opt for a hotel but it is not cheap. The area around is very nice so enjoy some scenic rides. But do not try off road in the national park!
From there you can go straight to Wroclaw but it would make more sense to choose B roads and see very cool rock formations (Skalne Miasto) located actually in Czech Rep. next to the place called Teplice Nad Metuji. You can head for Wroclaw the same day. It is a nice city with a great old town section and...some spectacular painting that is over 100m long (Panorama Raclawicka). How you get back to the Island is your choice from there.
Now, some word of advice.
Poles are nice to foreigners but hate Brits coming for stag nights. So don't join such groups.
Roads are generally ok for GS, there are very few highways (good) and very many one lane roads.
Overtaking is manic...only Romania beats Poland in this subject.
Police do not stop you without a reason and will not force you to pay a bribe. They cannot take anything from your bike either.
Laser speeding traps are common and penalty depends on the speed you rode. 40-50kmh over the limit will set you back for 500zl (£120).
Speed limits are 50kmh in town, 90kmh rural, 120kmh dual carriage and 140kmh highway. There is a 10kmh "redemption" over the speed limit so going 150kmh on the higway is still ok.
Alcohol limit is 2.5 times lower than in the UK (0.02%). Anything above UK limit of 0.05 is considered a crime and will put you in a serious trouble. You should not be drinking and riding anyway but be careful in the morning when not everything vapoured out.
Polish beer is quite strong (5-6%). Local food especially in Tatra mountains is superb.