Economists have suggested that "B" will cause an 8% fall in the value of the £ in the first year. As the £ goes down in value, prices of all imported goods will go up. Coronovirus ( the "C" word?) may do even more damage and as the enonomy crumbles there is no way of knowing how far down the £ will plunge although I expect a fall of about 15% by the end of 2021. The growing hole in government finances as it funds the battle against "C" will surely lead to higher taxation in some form. So you'll have less money in your pocket and what you have will buy less.
My advice is 'buy now' if you have the cash.