THERESA May is exiled in Blackpool, Helen Mirren is dusty, someone’s snapped Ken Dodd’s arm and Olly Murs fancies thinner cheeks. It can only be a documentary about Madame Tussauds: the Full Wax (STV, Wednesday, 9pm).

There is something inescapably odd about a waxworks museum, or as the subjects say on meeting their doubles for the first time, “weird”.

The first thing to note is that the models today are vastly superior to the ones you might recall. There is no “Who the heck is that?” here. In part this is due to the money, expertise and care spent, with some figures costing upwards of £100k to produce. For that dosh they had better look good. Research plays a part too, with number crunchers keeping an eye on who is in and out.

Nick Angel’s film starts in summer this year, just as the old dear on Marylebone Road is having a major revamp. Having opened there in 1835, Madame T’s now has branches around the world, but its heart remains in London and at the “proudly northern” Blackpool arm.

Blackpool is about to take possession of its newest subject, DanTDM. Gamer, YouTube phenomenon, musician, actor, and a gazillion other job titles, the 30-year-old from Aldershot is a perfect fit with the younger demographic Blackpool, and the other sites, need to attract.

In London, Little Mix are the latest new arrivals. There are also plans to reopen the Chamber of Horrors, closed in 2016 because it was considered bad taste but back by popular demand. Here, too, there will be upgrades. One idea is for the models to suddenly become animated and talk to the visitor. “Probably get punched,” was the prediction of one of the team.

We meet Craig Revel Horwood, whose Blackpool model is being spruced up and given some new duds. The Strictly judge says he dreads the day when the curators “retire” him due to lack of interest. Retiral is a delicate subject at Madame T’s. Out of respect models are not melted or binned. Instead their bodies are reused and the heads placed in a cupboard (far more respectful, I think you’ll agree). Other retirees find new homes behind the scenes (hence Theresa May’s trip to Blackpool, where she stands in the manager’s office). Some models are retired, only to roar back into relevance again, Boris Johnson, ex-London mayor turned PM, being the prime example of this. Wonder what happened to him?

Diane Morgan used to be a staple of Christmas playing Philomena Cunk in Charlie Brooker’s annual news round-up. Now the Motherland actor is in the schedules in her own right with her comic creation Mandy Carter. Ahead of a new run of her sitcom Mandy, there’s a festive special, We Wish You a Mandy Christmas (BBC2, Monday, 10pm).

Mandy is not a fan of Christmas. Even Christmas lasagne (“Are you calling the Co-op a liar?” she asks long-suffering nail technician and friend Lola (Michelle Greenidge) when she doubts the existence of such a dish. Instead of joining Lola and her sickly dog Tim for Christmas day, Mandy intends to watch Die Hard and get drunk. But three visitors have other plans for Mandy. Christmas, visitors, poorly Tim – you can see where this is going. It’s only 20 minutes long (there’s a repeat episode of Motherland after to fill the gap), but Morgan manages to pack in more funny lines than many a longer festive special (Mrs Brown anyone?).

For comedy value for money another show that has been hard to beat this year is Ghosts (BBC1, Thursday, 8.30pm). Stately home owner Alison (Charlotte Ritchie) can see ghosts but her other half Mike (Kiell Smith-Bynoe) cannot. What a cast of ghouls this lot are, from a Stone Age man and a scout leader to a Victorian lady and a disgraced MP (with no trousers). Jennifer Saunders guest stars – how is that for a seal of approval? – as Fanny’s mother, and all the regular cast are back for a half hour of chummy comedy.

Impeachment: American Crime Story, (BBC2, Tuesday, 10pm), reaches its conclusion. This retelling of the tale of Monica Lewinsky and Bill Clinton has been full of surprises. At first it seemed as though Lewinsky, a producer on the series, was going to have things all her own way. But the focus has gone beyond Lewinsky (played by Beanie Feldstein) to take in the other women involved, including Linda Tripp, the pal who recorded their conversations, and Hillary Clinton (Edie Falco).

Tripp (played by the always excellent Sarah Paulson) ends up a far more sympathetic character than she was first portrayed. Just a pity this redressing of the balance came too late: she died in April this year. The series is available on iPlayer and is well worth your time this Christmas.