Previous posters have said Tesla will honour prices from when the original order was placed.
Based upon past behaviour, if Tesla have repriced any part of the order, or the purchaser has amended their order, Tesla have used either...
the new total order price - all items priced at current book value so individual items can go up or down
or
the original total order price (not applicable to order amendments)
In the event of a Tesla price change, Tesla will automatically honour the lower of the above. If order has changed due to purchaser amendment, they will use the new total order price.
What Tesla have not done is mix and match individual prices between old and new order books.
I don't know the circumstances here, but some examples:
Base model reduction £1500, FSD price rise £1000. New price £500 discount - the £1500 reduction is offset by £1000 increase.
Base model reduction £500, FSD price rise £1000. Total order price remains same as original order as new order is more expensive.
Cycle carrier added at £1000, FSD price rise £1000. New order price increases £2000.