Gimmick

What's claimed to be United Kingdom's only hot spring (see also this list) is located bang in the center of the aptly named Bath in Southwest England. There's of course no guessing from where the namesake of the town comes from, it's too obvious.

Famed for both it's Roman remains situated around the natural spring as well as for the latter Georgian gentrification (lead photo above of the Circus), Bath seems to be top of the list for quite a few tourists to the UK. F.i. Tripadvisor puts Bath in it's top 10 of popular UK destinations with the baths being the most popular destination of Bath. Bath is also a UNESCO World Heritage site.

For us soakers there's two significant features in Bath:

* one: of course the Roman Baths, 

* two: the current day bathing facilities known as Thermae Bath Spa.

A sojourn to Bath is by no means cheap. Rated regularly as one of the most expensive places to stay in the UK (source), the costs of visiting some attractions in the city are not cheap either. Visiting the Roman bath remains will set you back a pound or 15, while a two hour stay at Bath's soaking establishment would set you back from 35-38 pounds; this no peanuts for us cheap skating natural soaking lovers.

But cutting back on costs is well possible if you choose to stay in nearby Bristol, a funky city along the lower Avon with a younger more worldly culture along it's harbour.

We thought that a bike ride from Bristol would be the way to go. To Bath.

There's a cycleway on the former track bed of a Bristol to Bath railway line. However the English (and with them the Tourist) see cycling as a summer activity, there was no way to rent a bike in winter.

Well, that meant a large part of our day was spent in vain in search of bikes; we then jumped on the train instead.

Seeing the prices mentioned, we had opted to make the Bath visit, a visit to just the Roman side of Bath.

Situated in the center of town next to the Abbey, late morning there's a line of visitors snaking it's way outside. That's encouraging! After being allowed in, we discover that there's another line to contend with, we had just be lining up to join the next line! 

Anyway, maybe 10-15 minutes in total we have our tickets and allowed access to the ancient springs themselves.

Someone has certainly gone out of their way to highlight and showcase the site / sights. Take an audio tour, it's an easy way to get more insight. I ended up following the on the hour tour guide who had even more insights, well worth it.

You'll discover a lot about how Roman's bathed, how the actual bathing took place, the wider surroundings of Bath and how the Roman baths were tweaked about becoming what they are today. 
Odd thing is that you can't actually bathe, as if this would be some kind of sacrilege. But maybe due to health issues (original lead piping?).

As said there were plenty of fellow tourists, it means that making the rounds is quite difficult, unless you have extreme patience.

I won't bore my readers with the history of the baths of Bath, there's plenty available on the internet. Check Bath's tourism website or owlcation.

Notable among the history was that in fact there's a pre-Roman history with the springs used by Celts with a deity being worshipped here, Sulis, a fact that even the Romans thought noteworthy hence they called Bath's baths Aquae Sulis. 
During the Roman times, the bathing establishment was in fact very well-developed, complete with piping and a jacuzzi. 
After the Romans surrendered their reign so did bathing; at least it seems to be the case for a few centuries. What has remained is that usage of the springs has always been an upper class thing, not necessarily for commoners ...

For those seeking a challenge in soaking in England, the Thermae Bath Spa seeks to entice you. Though it has excellent status on Tripadvisor, it's not always the case: overpriced, bad experience, expensive, gimmicky, a 90 minute wait to get in, run down and shabby, too busy are just some of the accolades, though most were very accomadating.
But these are just some of the recent reviews of the 5,000+ listed on Tripadvisor .... One should also note that the bathing etiquette is rather non-European so to speak.