A few thoughts, fwiw? My BC 26 is inboard diesel, saildrive.

extra weight....yes undoubtedly.
no ability to dry out.... Not so. I can, and do dry out. However, need to be very aware of the vulnerable saildrive.
extra drag when sailing. ...Not too bad. Saildrive aperture has a fairing diaphragm.  Folding prop.
loss of space...yes.
hassle of anodes etc...yes, especially  on a Beta Marine diesel/twin disc drive leg. They eat anodes. Fortunately,  as a Marine Engineer I do my own maintenance, in situ of of course.
trailer needs greater immersion, including hubs...yes, very much so. Immersing a double axle braked trailer can quickly/easily become very expensive and time consuming. My trailer has never been in the water, the boat being moved by a yard hoist and placed on the trailer, mast up. Original owner used to take the mast down (alloy - so crane required), then tow home behind a Land Rover for barn storage.  I have neither LR, nor barn; she lives in a yard near home. As before, the boat is launched in the spring, and recovered in the autumn.
My Storage fees include over-summering the trailer. It is too big/heavy to move by hand.

For me, the drying out issue is important, and, as I want to launch / recover the boat myself rather than pay for craneage, the trailer immersion is critical too.
...Yes... to me, the owners planned routine/cycle of usage is the key driver in "acceptability " of an inboard? Now in my 2nd season, it definitely works for me. Quiet, very economical, reliable, always immediately available (as is the fuel, there are several ports hereabouts where "bulk petrol" is not readily available.

Other things?
Obvioulsy...Trailer/train size/weight. My trailer maybe about a Ton MT, I fear? Towed it once behind my ordinary estate car. Not something I'd want to do regularly,  it definitely had control of the car. With boat loaded, it would be over 10m long (not that I'd be able to move it with the car, even if stupid enough to try)!
Years ago, as a group of pals, we campaigned an International 6m (almost 40ft, maybe 8T - perhaps more?) Towing a tri-axle trailer behind a very large US Ford F650 double rear wheel pick up. Towing to France decided for me that it was NOT the sort of thing that I wanted to do for a "holiday". This gets complicated,  and VERY expensive. Wealthier owners use especially converted 7.5 T flat bed lorries, towing the support rhib on a trailer. The very wealthiest,  adapted curtain side artics!

A BC 23 might be about my personal limit, financially and in terms of "nerve"?

I'm  fortunate,  in that I have pals with boats based in both Scilly and W Scotland, so no need to tow mine!

So...maybe don't dismiss an inboard, should one turn up - it might suit? But,  As far as I know, there are very few.

Thanks Rosieferg.  There are some obvious things in favour of inboards but some discussions outside this forum has given a list of things against:

extra weight
no ability to dry out
extra drag when sailing
loss of space
hassle of anodes etc
trailer needs greater immersion, including hubs

For me, the drying out issue is important, and, as I want to launch / recover the boat myself rather than pay for craneage, the trailer immersion is critical too.
 
Unfortunately, my budget won't stretch to your boat Rosieferg.  She looks really good - nice colour.

Hi There
I went through the same thought process re outboard v inboard engine but was completely (and I think correctly) convinced by Matt of Swallow Yachts that the boat is much better suited to having an outboard. And in fact there are I think very few built with inboards 
Reluctantly I am having to sell my boat, and wonder whether you might be interested. She was built in 2021, very high spec and in pretty much immaculate condition.  She is pale grey, with teak trim, performance rig, Garmin chartplotter, harken winches, Yamaha 9.9 outboard with electric start , brand new (never been in the water) custom made trailer. Sail no is 78. She has been sailed very little and is currently stored undercover.  Let me know if you would like more details and pic.

Wow Gareth - I'm impressed that you spotted this.  The fleet of Swallow Yachts is only visible for about 3 seconds!

Hi Andy
I’ve had several sources of fresh water leaking into the locker. The shower unit is certainly suspect no 1 - either it needs a new washer on the shower head connector, or  possibly just tightening, or else check the push-fit plumbing connections. I have had problems with elbows leaking both in the heads and near the pump. I think part of the problem is that on a boat we keep depressurising the system and to some extent it’s the water pressure that maintains the seals.
Next suspect is the socket for the tiller pilot in the seat/locker lid. This socket is subject to quite high forces and the lid isn’t very thick. I noticed mine was starting to move under load and leaked rainwater. I glued a wooden backing pad on the inside and reset the socket with epoxy and haven’t had any trouble since.
Another way I managed to get water in was via a towel that I hang off the rail under the locker lid. I realised one day that the towel was wet because I’d got one corner of it trapped under the lid and it had wicked water in from the channel at the back, surprising how much water was in the bottom of the locker as a result.
It might also be worth checking the drainage channels around the lid for hair-line cracks.