Vicar, now that you have had the on-the-fence answer, I am going to be the voice of dissent.
If I were a novice, no, I would not be looking at a rescue horse as a first horse. I would want a horse whose history I knew something about, and I would have wanted my instructor to also know the horse and whether it is personally suitable for me. If I trusted my instructor, I would allow her to guide me on the specifics of the horse, and to point out horses for me to try.
Unless you have a very experienced eye for horses, getting a horse from a rescue or the sales is a huge gamble. There are too many unknowns/risks with rescues (and sale) horses. There will be posters who follow who say "I got a horse from a rescue/sale, and its a success story' but remember that might be some years down the track, and is the exception, not the rule.
Even as an experienced rider, I would not get a horse from rescue or the sales, period. A 4* eventer that I know rescued a horse from a sale to turn around, retrained it, and then passed it onto a novice rider that I know. After a few months, it was obvious that the horse was not suitable for the novice rider, and she had to get another trainer to help her to sell it at a loss.
Please keep asking questions, I can tell you are learning lots
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