When I lived back in England, we used to use Youth Hostels in various parts of the country for a weeks training if we didn't jet off to somewhere sunny.
Carbisdale Castle in the north of Scotland is (was - don't know about now) probably one of the best youth hostels in the UK.
If I remember correctly, its the wooden wall panel under the stairs, behind the white statue, that "opens" to reveal a mysterious passageway.
An impressive stately home that was given to the YHA and features "classic" Scooby Doo like statues that turn to open secret passageways... I sh1t ye not. It's way up in the north of Scotland but well worth the trip in the summer months. Even in spring the weather can be best described as hostile if the dark clouds roll in off the Atlantic. I think the number of cars we saw on the main roads that week could be counted on both hands...
... but the ride back from Scourie into driving rain and headwinds that almost brought one to a trackstand were something I'll never forget.
Bridges Youth Hostel at Long Mynd, Shrewsbury is a fantastic cyclist friendly Youth Hostel. Not flash like Carbisdale - think utilitarean - but great countryside for riding, great kitchens, a secure room for the bikes and as youth hostels go - comfy beds. The hostel itself is fairly nice.
Ilam (ilam) Hall in Derbyshire is almost as epic as Carbisdale and is based on a 100+ acre country estate. The country roads around there are great for cycling - just to the south of the Peak District.