Is it possible to just wander around and "do your own thing", or are you herded around in groups? I know it's quite expensive, but I would love to see inside it. No intention of attending a service.
You get to go in the Chapel when you visit the Castle, as long as it is open, you would need to check, they should know in advance. When we went in last summer, we wandered round on our own. And when you get tickets for the Castle, you can have them upgraded for free as an annual pass, so can go again as often as you like within the year, but you still need to book a slot in advance. If you were staying locally you could go in several times if you wanted to. There's so much to see in the Castle, it's hard to take it in 1 visit.
Must be 6 years or so since I last went (actually went twice on the annual ticket/pass), and we wandered around chapel at our leisure, BUT we did go at a quiet time with relatively few people visiting the castle.
With the recent passing of the Queen, I'd imaging demand to visit is much higher, so more restrictive visiting rules maybe should be expected, I'd check with the web site/ticket office before travelling.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.