Hello Matova ...
I have noticed that you haven't had many replies to your question, so I thought I'd try to give you a few pointers. I apologise in advance if I am telling you things which you already know.
First, there are Organists' Associations in all the counties in England (and also Scoltanld and Wales I think too). There are detail;s here:
http://iao.org.uk/associations/I am sure that the secretaries of these associations would welcome you to their meetings if you happen to be in their areas at the right time. They will also be willing I'm sure, to advise you on organs to see in their areas. At most meetings members get a chance to play the organs in the places visited.
Secondly: you will know that there are about six times as many pipe organs across the UK as there are in the US, with a population that is actually only a sixth of the US! I mention this because it means that you are
always near a pipe organ in the UK! If you want large organs (e.g. by Willis, Harrison & Harrison, Hill Norman & Beard), you just need to visit the Cathedral Cities (Salisbury and Hereford you'll know about, but Lincoln, Wells, Gloucester, Ely, Bath, Liverpool, etc etc) plus the London Abbeys and Cathedrals) - there are a great many more of these, as I'm sure you know. There are organ recitals, mostly free-of-charge (leave a donation) every week in all of them. But there are also many large and small parish churches with organs - thousands, I'd say! They mostly have websites, and the telephone numbers of the Churchwardens are usually published - they will usually be able to contact their organists for you - surely most organists are delighted to show off their instruments!
Then, there are concert organs in many cities - the Royal Festival Hall organ has just been refurbished (as you'll know from the forum thread), and the Royal Albert Hall has recitals too. Birmingham has two large concert organs (Symphony Hall and Town Hall), Manchester has a notable recent organ in the Bridgewater Hall. I could go on! But I'll stop there!
I hope that you enjoy your tour!
Best wishes
Ken.