Once the LPA is registered with the OPG, it is of course active as I mentioned earlier. You can do all sorts of financial dealings, BUT, the donor MUST agree to what you propose. You can only make decisions without the donors agreement, once capacity is lost. Health and Welfare LPA is different though and can only be used once capacity is deemed lost. So you can't be forced to take a Covid shot - but when capacity is lost then it's up to the attorney.
durhamlad. - Your son can register the LPA with your bank and anywhere else that YOU choose. He can't go against your wishes until you have lost mental capacity, (hopefully never). The LPA should be looked upon as making life easier for those with physical disabilities that simply can't leave the house easily to undertake financial dealings.
People in their 20 register LPA's. All perfectly healthy, but consider catastrophic events that could, heaven forbid, leave them without mental capacity. High risk occupations, or hobbies where there is a real danger. Sometimes newly weds decide on this LPA course, as part of long term planning. Clearly, the attorneys not looking to sell the donors home under them; as soon as the registration is complete. There are protections in place, with a third party notification of change.
Failure to make an LPA(s), but then to ultimately need them, can cause a real headache with the Court of Protection.
Prices are about £100 per LPA and easy enough for DIY. If you get something wrong, then they'll fire it right back to you. At least you know it's all in place, (unlike a DIY Will Kit) and ready for something; we all hope will never happen...